Optical distributor for room lighting

ABSTRACT

An optical distributor ( 10 ) is formed as a reflector with one or more sloping surfaces. The sloping surfaces have varying angles of inclination from a bottom edge ( 20 ) to a top edge of the reflector. The sloping surfaces may form a substantially pyramidal or conical frustum-shaped surface. The sloping surfaces may additionally or alternatively form a band of adjacent or contiguous faceted surfaces. The reflector is configured to receive light rays through an opening ( 32 ) in a first plane ( 30 ) and reflect light rays radially outward and upward at varying angles of reflection ( 8 B) to a bottom surface of the first plane ( 30 ) in a manner that illuminates both the bottom surface of the first plane ( 30 ) and an area ( 40 ) below the first plane ( 30 ). The reflected light may illuminate the first plane ( 30 ) and the area ( 40 ) below in a substantially uniform manner.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the national stage application of PCT PatentApplication No. PCT/US2011/056595 filed 17 Oct. 2011, entitled “Opticaldistributor for room lighting,” which claims the benefit of U.S.Provisional Application No. 61/393,684, filed 15 Oct. 2010 entitled “Amethod, an apparatus, and a computer program product for an opticaldistributor” both of which are hereby incorporated herein by referencein their entirety for the purposes of PCT Rule 20.6.

TECHNICAL FIELD

The subject matter described herein relates to optical distributors, andmore specifically to optical distributors for distributing rays oflight.

BACKGROUND

Some optical reflectors are conical and include a 45 degree reflectingcone, which reflects light rays from a collimated or quasi-collimateddownwelling beam through a 90 degree angle, spreading the lightlaterally and equally through a horizontal angle of 360 degrees to thewalls of the room. Such reflectors, however, may only illuminate thewalls and corners of the room, leaving the central area of the roomdark, and may produce a glare condition if the reflected light entersthe eyes of occupants or if light scattered from its surface toward theeyes of occupants is too bright. If a single conical reflector's angleof reflection is tilted upward somewhat, so as to spread the light overthe ceiling rather than on the wall, the light may be better distributedover the whole room area. The tilting, however, may induce a ring ofreflected light on the ceiling which, following its diffuse reflectiondownward to a task plane, still may not produce a generally uniformillumination of the illuminated space.

The information included in this Background section of thespecification, including any references cited herein and any descriptionor discussion thereof, is included for technical reference purposes onlyand is not to be regarded subject matter by which the scope of theinvention as defined in the claims is to be bound.

SUMMARY

The various embodiments of optical distributors described herein allowlight rays from a light source, such as a solar light source, to bereflected and propagated onto one or more areas to be illuminated. Insome of the embodiments of an optical distributor described herein, oneor more faceted surfaces may reflect the light rays in a manner toilluminate an area in one or more rooms or provide general illuminationof a whole room or multiple rooms in an approximately uniform manner. Insome embodiments, the faceted surfaces may be frustum-shaped or they maybe polygonal or circular in shape and form the exterior surface of theoptical distributor. In other embodiments, the faceted surfaces mayextend in only one direction and may be substantially rectangular shapedin the other two directions. Still other embodiments are describedbelow.

In some embodiments, the optical distributor may include a craterportion and in some embodiments may further include a cone-shaped insertwithin the crater portion. In some embodiments, the optical distributormay be pyramidal-shaped, cone-shaped, frustum-shaped, dual intersectingplanar-shaped, trough shaped, and so forth.

Various embodiments, as described in more detail below, may include andincorporate none, one, or several of the following: blocking rings,glare shields, optical elements (such as a lens or a diffusing sheet),light pipes, and so forth.

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter. A moreextensive presentation of features, details, utilities, and advantagesof the present invention as defined in the claims is provided in thefollowing written description of various embodiments of the inventionand illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of one embodiment of an optical distributor.

FIGS. 2A and 2B are schematic side plan views of another exemplaryembodiment of an optical distributor.

FIG. 3 is a schematic view of one embodiment of an optical distributor.

FIG. 4 is a schematic side plan view of one embodiment of an opticaldistributor showing the reflection of rays from a reflector 10.

FIG. 5 is a schematic side plan view of one embodiment of an opticaldistributor showing the reflections of rays from a reflector 10 andsecondary reflections of those rays from a first plane 30 onto a secondplane 40.

FIG. 6 is a schematic diagram of a portion of one embodiment of anoptical distributor showing the geometrical relationships of components.

FIG. 7 is a schematic diagram of a portion of one embodiment of anoptical distributor showing further geometrical relationships ofcomponents.

FIGS. 8A and 8B are schematic diagrams of portions of one embodiment ofan optical distributor showing further geometrical relationships ofcomponents.

FIG. 9 is a schematic bottom plan view of a plane with optical raysreflected onto the plane by one embodiment of an optical distributor.

FIG. 10A is a schematic side plan view of one embodiment of an opticaldistributor with glare shields.

FIG. 10B is a schematic isometric view of one embodiment of an opticaldistributor with glare shields.

FIGS. 11A and 11B are schematic diagrams of portions of one embodimentof a glare shield for an optical distributor showing certain geometricalrelationships of components.

FIG. 12 is a cross-section view of one embodiment of an opticaldistributor.

FIG. 13 is a schematic diagram of a cross-sectional portion of anoptical distributor showing geometrical relationships of components.

FIG. 14 is a schematic diagram of a portion of an optical distributorshowing geometrical relationships of dimensions and an angle.

FIG. 15 is a schematic diagram of a cross-sectional portion of anoptical distributor showing geometrical relationships of components.

FIG. 16 is a schematic diagram of a portion of an optical distributorshowing geometrical relationships of components.

FIG. 17 depicts two wire frame isometric views of one embodiment of anoptical distributor.

FIG. 18 is a schematic side plan view of one embodiment of an opticaldistributor showing the directions of propagation of some optical raysincident on that distributor.

FIG. 19 is a schematic cross-section view of one embodiment of anoptical distributor.

FIG. 20 is a schematic isometric view of one embodiment of an opticaldistributor.

FIG. 21 is a schematic view of portions of one embodiment of an opticaldistributor.

FIG. 22 is a schematic view of portions of one embodiment of an opticaldistributor.

FIG. 23 is a schematic view of portions of one embodiment of an opticaldistributor.

FIG. 24A is a schematic view of one embodiment of an opticaldistributor.

FIG. 24B is a schematic view of one embodiment of an opticaldistributor.

FIG. 25 is a schematic view of one embodiment of an optical distributorused to illuminate two rooms from a cut-away wall.

FIG. 26 is a schematic top plan view of one embodiment of an opticaldistributor similar to that shown in FIG. 25, but designed to illuminatefour rooms with cut-away walls.

FIG. 27 is a schematic isometric view of one embodiment of an opticaldistributor shaped as a pyramidal frustum.

FIG. 28 is a schematic isometric view of one embodiment of an opticaldistributor.

FIG. 29A is a schematic isometric view of portions of one embodiment ofan optical distributor.

FIG. 29B is a schematic isometric view of portions of one embodiment ofan optical distributor.

FIG. 29C is a schematic isometric view of portions of one embodiment ofan optical distributor.

FIG. 30 is a schematic cross-section view of one embodiment of anoptical distributor.

FIG. 31 depicts two isometric views of embodiments of an opticaldistributor, one installed in a room with a circular perimeter and theother installed in a room with a rectangular perimeter.

FIG. 32 is a schematic side plan view of two optical distributorsinstalled in a single room.

FIG. 33 is a schematic isometric view of portions of one embodiment ofan optical distributor.

FIG. 34 is a schematic view of portions of one embodiment of an opticaldistributor.

FIG. 35 is a schematic view of portions of one embodiment of an opticaldistributor.

FIG. 36 is a schematic view of portions of one embodiment of an opticaldistributor.

FIG. 37 is a schematic view of one embodiment of an optical distributor.

FIG. 38 is a schematic view of a portion of one embodiment of an opticaldistributor.

FIG. 39 is a side plan view of one embodiment of a portion of an opticaldistributor.

FIG. 40 is a schematic diagram of a portion of one embodiment of anoptical distributor showing the geometrical relationships of components.

FIG. 41 is a schematic diagram of a portion of one embodiment of anoptical distributor showing the geometrical relationships of components.

FIG. 42 is a schematic isometric view of one embodiment of a linearoptical distributor.

FIG. 43 is a schematic isometric view of one embodiment of a linearoptical distributor with a center well.

FIG. 44 is a schematic diagram of a specifically configured computerdevice for generating size, angle, and form specifications for anoptical distributor.

DETAILED DESCRIPTION

In general, an optical distributor, which may also be referred to as aradial optical distributor, a distributing reflector, an apparatus, acone, a conical reflector, a reflector, a distributor, a linear opticaldistributor, a polygonal optical distributor, an optical element, and soforth, may be referred to herein simply as an optical distributor maytake many different forms, some of which may depend on the environmentor room or apparatus in which the optical distributor is to be used.Multiple embodiments of optical distributors are described herein. Forexample, FIG. 1 depicts a radial optical distributor 10; FIG. 21 depictsa quasi-planar reflector 50 as an optical distributor; FIG. 24A depictsa pyramidal, frustum-shaped optical distributor 15A; FIG. 24B depicts acurved surface version of FIG. 24A; FIG. 33 depicts an opticaldistributor including a refractive lens element 21; FIG. 37 depicts alinear optical distributor 100; and so forth.

Though the primary use intended for this technology is for solarlighting of interior spaces of buildings or other structures, it mayhave use in a variety of other applications, from scientific instrumentsto electric lighting to medical devices to industrial process heating,etc. Thus, the word “light” as used in this application and the claimsbelow is intended to include both visible and invisible radiation overother parts of the electromagnetic spectrum, including the visibleportion normally called light. The use of the term “light” herein shallnot be construed to exclude the use of this technology for otherapplications using predominantly UV, infrared, or other invisibleradiation. The use of the term “illuminate” herein is intended toinclude radiation in all portions of the electromagnetic spectrum, notjust in the visible portion thereof.

Methods for determining appropriate design parameters (e.g., dimensions,angles of incidence, etc.) for the multiple general types of opticaldistributors and several variations on the optical distributors andmethods are also described herein. It should be noted that the variousmethods for determining design parameters, as well as the variations onthe optical distributors and other discussion of the opticaldistributors contained herein may in some cases apply, with appropriatemodifications (if any), to more than the specific type of opticaldistributor with reference to which the method or variation isspecifically described. For example, the various mathematical operationsdescribed in connection with FIGS. 6 through 8 may apply, withappropriate modifications (if any), in some cases to both a radial-typeoptical distributor and a linear-type optical distributor, as well asother types of optical distributors. For purposes of brevity, however,the methods and modifications described with respect to one type ofdistributor may not necessarily be repeated with respect to another typeof distributor, even though such methods and modifications may beequally applicable to both.

It should be noted that both radial and linear optical distributors aregenerally specularly reflecting, without significant diffuse reflection,while the under or lower side of a reflecting plane (e.g., a ceiling)are generally diffusely reflecting, and these conditions are generallythe intent in subsequent descriptions of this technology. However, theselimitations are not generally required for the efficacy of thistechnology. For example, an optical distributor may work well even whenthe distributors have substantial diffuse components to theirreflectance property.

In an in initial example, FIG. 1 shows an isometric view of aradial-type optical distributor 10 that may distribute light initiallypropagating in a cylindrical, collimated beam of light rays 8A, byreflecting the beam of light rays 8A towards a bottom surface of a firstplane 30 (which may in some embodiments be a nominally circulardiffusing plane). The optical distributor 10 may in some embodiments befaceted, conical, reflective, radial, etc., and the beam of light rays8A may propagated to the optical distributor 10 by passing through acircular or polygonal opening or hole 32 in the first plane 30 (such asa ceiling). In this description and those that follow for variousembodiments, the collimated beam of rays 8A may come from an electriclight source system or from a solar collecting and concentrating system.In both cases, the rays 8A in the beam may be well-collimated (i.e.,varying little from being parallel to optical axis 5) or they may be“quasi-collimated” (meaning that they vary from a small angle, e.g., 0.5degree up to approximately 5 or 10 degrees from the direction of theoptical axis 5).

For incident beams of this kind having an ever greater spread ordivergence from the direction of the optical axis 5, the variousembodiments described below may or may not perform less well, but maystill be efficacious for certain applications. In the followingdescription, the word “collimated” is used to include well- andquasi-collimated beams. However, the technology can certainly be usedwith incident beams having greater divergence than suggested above. InFIG. 1, only a portion of the light rays filling the collimatedcylindrical beam are depicted as dashed arrows 8A lying in a planethrough a diameter of aperture 32 in plane 30. That drawing conventionis followed in the figures to represent the full complement of fluxcontained in the cylindrical beam passing through aperture 32.

In some embodiments, a substantially collimated beam of light 8A may beused to illuminate the optical distributor 10 because the collimatedbeam of rays 8A may allow for a more controlled distribution of therays. In other words, because the orientation of the rays 8A may begenerally parallel (e.g., collimated), an optical distributor may insome instances be used to control the distribution of the rays across anarea to be illuminated. On the other hand, rays that are not collimated(or at least quasi-collimated) may be more difficult to control via anoptical distributor because of the lack of uniformity of the orientationof the light rays. In some embodiments, however, rays that are notcollimated may be efficacious for the intended application.

Returning to FIG. 1, the radiant flux diffusely reflected from the firstplane 30 may subsequently be approximately uniformly distributed (e.g.,with approximately constant irradiance or illuminance) through controlof the shape of the optical distributor 10 across a second plane 40,with the second plane 40 being not far below the first plane 30 in someembodiments, or the illumination distribution following reflection fromplane 30 may be substantially varying, with higher illuminance orirradiance values in one or more portions of plane 40, and less inothers. Control of the shape of the specular reflectors forming theoptical distributor 10 can be used to direct the reflected radiation inany of a variety of ways toward a variety of targets surrounding theoptical distributor 10. In other embodiments, the second plane 40 may befar below the first plane 30. The second plane 40 may be parallel, andmay be, for example, the floor or task plane (e.g., desk or counterheight) of a space to be illuminated, but it may alternatively be anytarget to be illuminated or irradiated.

The optical distributor 10 may thus redirect or distribute light fromthe collimated beam into other directions in a controlled manner. Byshaping the optical distributor 10 into a stack of rings shaped asfrustrums of right circular cones of different inclination angles andincreasing the number of rings of reflected flux, and when used with asource such as a solar disk that may have a small natural angularspread, the individual rings of light on the first plane 30 may bebroadened by the slight angular spreading and fill the target area ofthe first plane 30 more uniformly. As such, the radial opticaldistributor 10 may illuminate some, most, or all of the second plane 40in an approximately uniform manner. Also, the illumination of the firstplane 30 may be substantially discontinuous, but the rings may besufficient in number as not to be overly discontinuous or too bright atany particular location as a result of the optical distributor 10redirecting the light rays. It may be desirable to prevent the smallerarea of plane 30, which is immediately above and hence closer to theoptical distributor 10, from being excessively brighter than areas ofplane 30 radially further outward, which may then be too dim, by varyingthe quantity of flux distributed to plane 30 so that most of the fluxfills the greater areas around the outer perimeter of plane 30.

In some embodiments, the optical distributor 10 may include one or moresegments of one or more circular conical facets (or sections orfrustums), some or all of which may have a slightly different angle froma vertical line through the center of the optical distributor, which maybe the axis 5 of optical distributor 10. The facets or faceted surfaces(or the segments thereof) of the optical distributor 10 may further haveslightly altered widths and tilts so that the illuminance or irradiancewithin all of the reflected rings of light onto the first plane 30 maybe, on average, approximately the same, thereby distributing the lightacross the second plane 40 somewhat evenly.

In other embodiments, the optical distributor 10 may be formed as asmooth and quasi-conical reflective surface with a continuously changingslope. The surface may redirect or distribute a portion of a downwellingcollimated cylindrical beam of light rays 8A back upward and radiallyoutward onto a first plane 30, in such a manner that the light from theoptical distributor that is subsequently reflected diffusely from thefirst plane 30 may thereafter be generally uniformly distributed over asecond plane 40 below the optical distributor 10. The opticaldistributor 10 in this embodiment is the natural result of taking thenumber of frustum rings to an upper limit and fitting a continuous curveto the points on the boundaries between each of the frustum rings.

Many variations of the radial optical distributor 10 shown in FIG. 1 arepossible. For example, the first plane 30 may have a lower surface thatis diffusely reflecting, and the surface may have any perimeter, shape,width, etc. The first plane 30 may have a circular or polygonal opening32 in its center, may be centered around the optical axis 5 of theoptical distributor 10 (as illustrated in FIG. 1). Furthermore, the topor peak of the radial optical distributor 10 may be located at anydistance below the first plane 30 and may or may not be truncated at thetop, leaving a hole in its center through which incident flux can pass.As described below in more detail, some embodiments of the radialoptical distributor 10 may be low-profile in order to reduce thedistance that the optical distributor 10 extends below the first plane30. In other embodiments, which are described in more detail below, astack of shallow conical glare shields may surround at least a portionof the optical distributor. Still other embodiments, as described below,include one or more tilted reflective mirrors that may be elliptically,rectangularly, or trapezoidally shaped and which may reflect a portionof the vertical downwelling collimated beam of light rays radiallyoutward from the central axis of the beam, while spreading the lightrays laterally and optionally in the perpendicular direction as well, toilluminate one or more limited portions of the surrounding space withcontrolled levels of illumination.

Although the nominal shape of the incident beam of light rays 8A shownin FIG. 1 is approximately cylindrical and may result in approximatelyuniform irradiance or illuminance in the reflected light when used witha radial optical distributor 10, other shapes of incident light beamsand/or other shapes of optical distributors are possible. Incident lightrays may form a rectangular beam, a polygonal beam, an elliptical beam,or any other type of beam, including a beam with an irregular crosssection. The optical distributor 10 may be appropriately modified fordiffering incident beam shapes. For example, in the case of anelliptical light beam, the optical distributor may be deformed to have amatching elliptical base perimeter.

The optical distributor 10 may in some cases be used to illuminate aroom or a portion thereof using solar light collected by a lightgathering system. In some embodiments, the light gathering system may belocated on a rooftop and may deliver a generally fixed, nominallycylindrical beam of light downward through the roof and ceiling and ontothe optical distributor using a single roof penetration.

FIG. 2A shows a side plan view of a reflecting optical distributor 10with four faceted surfaces (10A, 10B, 10C, and 10D) and a stray raysblocking ring 25 (which may also referred to as a reflective ring orblocking edge). The blocking ring 25 may, in some embodiments, beopaque, absorbing, reflecting, and/or diffusely reflecting ortransmitting, and may be located around the base 20 of the opticaldistributor 10 and extend some distance radially outward beyond the base20 of the optical distributor 10. The blocking ring 25 may redirectstray flux from the incident beam of light rays 8A and propagate themradially outward beyond the perimeter of the base 20 of the opticaldistributor 10 and thence upward onto first plane 30, which flux mightotherwise cause a glare or stray light condition. Many variations on theblocking ring 25 shown in FIG. 2A are possible. In some embodiments anoptical diffusing sheet 26 (as shown, for example, in FIG. 30, but whichshould be extended radially beyond the distributor 10 to interceptdownwelling rays which may miss that distributing reflector) may be usedin conjunction with or in place of the blocking ring 25.

FIG. 3 depicts an optical distributor 10 with a blocking ring 25positioned between a first plane 30 and a second plane 40. The firstplane 30 shown in FIG. 3 has a circular opening 32 through which a beamof light rays may pass to reach the optical distributor 10 and fromthere, be reflected onto a bottom surface of the first plane 30.

FIG. 4 shows a side plan view of an optical distributor 10, and alsoshows the approximate paths of optical rays initially contained withinthe incident cylindrical beam 8A propagating downward through theopening 32 in the first plane 30 onto the optical distributor 10 with ablocking ring 25 around it and thence as rays 8B upward and outward ontothe bottom surface of the first plane 30.

FIG. 5 shows a side plan view of an optical distributor 10, and alsoshows the approximate additional paths followed by optical rays 8Bdiffusely reflected by first plane 30 propagate from the bottom surfaceof the first plane 30 downward onto the second plane 40. The raysdepicted in FIG. 5 are distributed in an approximately uniform manneracross the second plane 40.

FIGS. 6 through 8B show schematic diagrams of portions of an opticaldistributor 10 with various geometrical lines, dimensions, and anglesillustrated for use in explaining various mathematical steps that may beused in some embodiments to compute potential dimensions of someembodiments of the optical distributor 10. Referring to FIG. 6, the line5 is an axis through the center of the optical distributor 10, denotedas the y-axis, and line 30 in FIG. 6 coincides with and corresponds tothe first plane 30 in FIG. 1, and is denoted the r-axis in FIG. 6. Thearrows 8A in FIG. 6 depict some of the downwelling light rays in thecollimated incident beam propagating downward toward the facetedsurfaces 10A, 10B, 10C, and 10D of the optical distributor 10. FIG. 6also shows the radial limits of some target regions on the bottomsurface of the first plane 30.

Still with reference to FIG. 6, an optical distributor 10 may bevisualized by defining a set of coplanar line segments 10A, 10B, 10C,10D, and so forth, in the r-y plane of a rectangular coordinate system,and sweeping the coplanar line segments 360 degrees around the opticalaxis 5 to form a three-dimensional segmented conical surface. Thecoplanar line segments 10A, 10B, 10C, 10D, when swept around 360degrees, may represent the faceted surfaces 10A, 10B, 10C, 10D shown,for example, in FIG. 2. The radial widths, heights, and tilt angles ofthe facets or segments of the optical distributor 10 may be selected toreflect light into annular or ring areas in the first plane 30 in such amanner that the light rays diffusely reflected from the first plane 30are approximately uniformly distributed across the second plane 40.

In FIG. 6, a downwelling flux of light rays 8A may strike the linesegments, 10A, 10B, 10C, and 10D in the four-segment or four-facetoptical distributor shown in FIG. 6. The flux may reflect specularly upand radially to the left of the portion of the optical distributordepicted in FIG. 6, with rays at the ends of the line segmentspropagating onto the first plane 30. Measuring the distance down fromthe first plane 30 as coordinate y and radial distances to the left fromthe optical axis 5 as coordinate r, line segment 10A has top rightcoordinates (r₁₁, Y₁₁) and bottom left coordinates (r₁₂, Y₁₂). Becausethis line segment 10A is connected to the second one, 10B, it may have,but is not restricted to, top right coordinates (r₂₁, Y₂₁) which are thesame values as the coordinates (r₁₂, Y₁₂) of the bottom left end of thefirst line segment 10A. Rays reflecting from line segment 10A maypropagate through the cross-hatched region on FIG. 6 until they strikethe first plane 30 between radii R₁₁ and R₁₂, respectively, inside thefirst target annulus having inner radius R₁ and outer radius R₂.Similarly, light rays striking the second conical facet, illustrated inFIG. 6 as line segment 10B, may reflect up and to the left of the firstplane 30 arriving between radii R₂₁ and R₂₂ inside the target annulushaving inner and outer radii R₂ and R₃, respectively. The angle betweenthe rays reflected from line segment 10A and plane 30 is designated θ₁and the corresponding angle for rays reflected from the next linesegment, 10B, is θ₂, etc. Increasing the radial widths R_(i2)−R_(i1) forthe i^(th) reflected beam onto the first plane 30 in a certain way mayproduce a similar average illuminance in each of the rings of reflectedlight onto the first plane 30. To achieve approximately uniform fluxlevels and distributions across the first plane 30, the widths Δr_(i)and angles of tilt φ_(i) of the line segments 10A, 10B, 10C, etc. usedto generate the shape of the optical distributor 10 may be adjusted.

Certain mathematical operations will now be described with reference toFIGS. 6 through 8, and later, with reference to FIGS. 13 through 16.These mathematical operations may be used in designing some but not allembodiments of a radial optical distributor. Other mathematicaloperations may be used in place of, or in addition to those explainedbelow. Also, the mathematical operations explained below may be modifiedin some instances.

The first plane 30 is divided into N circular rings or annular “target”zones of equal radial widths ΔR_(o) given by Equation (1).ΔR _(o)=(R _(N+1) −R ₁)/N  (1)The area Ai of the i^(th) zone, given byA _(i)=π(R _(i+1) ² −R ₁ ²)  (2)increases linearly with R_(i) because the radial widths of the targetzones may all share the same value, ΔR_(o), as shown in equations (3)through (8) below. For the average flux density or irradiance orilluminance to be the same for each area A_(i), the reflected beam goinginto each target zone on the first plane 30 may contain an amount offlux that increases linearly with respect to this area, so that theaverage illuminance will be the same for each area A_(i). In general,the i^(th) conical distributor segment illuminated area on the firstplane 30 will not fully fill the target area A_(i). Due to beamspreading if the sun is used as the light source and as the number N ofdistributor segments increases, there may be a degree of filling in ofthe unilluminated gaps on the first plane 30 and as N is increased, andan increasing overlap of the adjacent illuminated rings on the firstplane 30.

Since each target annular area or ring may have the same radial widthΔR₀, it is next shown that the area A_(i) of each ring may generallyincrease linearly with respect to the inner circle circumferenceC_(i)=2πR_(i). The derivation with respect to C_(i) results in a formulafor the desired area A_(i) of the i^(th) zone as follows:A _(i)=π(R _(i+1) ² −R ₁ ²), i=1 to N  (3)ΔR=R _(i+1) −R _(i)  (4)Then ΔR may be set to be constant so thatR _(i+1) =R _(i) +ΔR  (5)Square both sidesR _(i+1) ² =R _(i) ²+2ΔRR _(i) +ΔR ²,substitute this result into (3), and rearrange the resulting equation asfollows:A _(i)=π(R _(i) ²+2ΔRR _(i) +ΔR ² −R _(i) ²)  (6)A _(i)=π(2ΔRR _(i) +ΔR ²)  (7)A _(i) =πΔR ²+2πΔRR _(i)  (8)This derivation shows that areas A_(i) increase linearly with the radiiR_(i). If C_(i)=2πR_(i) is the circumference of the inner circularboundary of the i^(th) annulus, the changing area of each annulus ofconstant width depends either linearly on the circumference,A _(i) =πΔR ² +ΔRC _(i)  (9)or also linearly with the radius,A _(i) =πΔR ² +ΔR2πR _(i)  (10)

By increasing the radial widths Δr_(i) of the i^(th) frustrum-shapedsegments of reflector 10 linearly with i, an increase in the quantity offlux in the incident beam 8A may be intercepted by each such segment andthereby sent to the target zones on first plane 30, causing the flux ineach area A_(i) of that plane to increase linearly as well to match thelinear increase in the areas A_(i). This results, in principle, in theratio of flux to area of each target zone to be constant, producing thedesired uniform average irradiance or illuminance of the total targetarea of plane 30. The derivation below leading to Equations 68-82explains how to design the distributing reflector 10 to achieve thisresult.

With reference to FIGS. 6 through 8, the inner radius of the opticaldistributor may be called R_(IN) (which may be nonzero if it is desiredto have a circular or polygonal opening or aperture in the top of it)and the outer radius of the base 20 of the optical distributor may becalled R_(OUT). Next a designer may decide how far below the bottomsurface of the first plane 30 the top of the optical distributor shouldbe placed (i.e., the value of y₁₁), and this distance may in someembodiments be small enough that the bottom of the optical distributordoes not protrude too far down into the space below the first plane 30.Finally, a designer may determine the length of the innermost radius ofthe illuminated area on the first plane 30. That is R₁₁, also calledR_(min) and may be the same as R₁ in FIG. 6. The target zones on thefirst plane 30 may be of different radial widths, or they may bedesigned to all be the same radial width, ΔR_(o)=R₂−R₁=(R_(N)−R₁)/N.Next, a designer may determine that the innermost edge of the reflectedflux ring on the first plane 30 from the i^(th) conical distributorsegment should be coincident with the innermost radial zone R_(i) insome embodiments. In these embodiments, the outer radial edge of thei^(th) reflected beam flux ring on the first plane 30 may increase withi so that the total flux in the i^(th) reflected flux ring increaseslinearly with the inner radius R_(i). This may result in the illuminatedring within each of the N zones on the first plane 30 not always fillingthe target zone area, making the illumination of the bottom surface ofthe first plane 30 binary in nature (a set of bright rings separated bydark spaces between them).

Various steps may be taken in some embodiments to overcome the binaryillumination of the first plane 30. For example, the shape of eachsegment or facet of the optical distributor may be adjusted to force thereflected light from each segment to fill its target ring completely.This may be accomplished by using convex and/or concave segments orfacets for the optical distributor, so as to spread the collimated lightrays incident on each segment or facet fully over its target zone on thefirst plane 30.

As another example, in some embodiments the incident downwellingcollimated beam of light rays may spread to fill a solid angle of somesmall size, which may be called “quasi-collimated.” Such a condition maycause the reflected flux of light rays from each optical distributorsegment or faceted surface to spread out radially and/or longitudinallyinto the dark spaces between the reflected beams, thereby softening thecontrast and improving the uniformity of illumination across the firstplane 30. Imperfections in the optical system delivering the beam oflight rays 8A to the optical distributor may produce a degree ofspreading of the downwelling beam and this may help to further spreadthe flux reflected from the optical distributor.

As another example, the number N of distributor facets and correspondingtarget zones on the first plane 30 may be increased, making the darkspaces between each reflected beam reaching the first plane 30 smaller.If there is also a slight divergence in the downwelling quasi-collimatedbeam, as indicated above (e.g., when the sun is the source), the darkspaces may be filled in by the spreading beams of flux due to the slightdivergence.

As still another example, once the coordinates of all the line segmentshave been calculated as described above, a smooth curve may be fitted tothe starting points (r_(i1), y_(i1)) (or r₁, y₁ in some embodiments) ofeach segment while increasing N to 20 or 30 or more. Such a curve fitmay be obtained using a second order polynomial. Other curve fitequations may also be employed. The resulting curve may be smooth andmay produce an approximately continuous distribution of flux on thefirst plane 30 that is approximately uniform in irradiance orilluminance. When N is set equal to 30, a second order polynomialprovides a good curve fit and a continuous surface profile for thedistributor that produces uniform illumination of plane 30 usingquasi-collimated concentrated solar radiation.

FIG. 7 is a schematic illustration of a cross section of an opticaldistributor, detailing the i^(th) one of several segments or facets ofthe optical distributor 10 and the i^(th) circular “target” ring ofradial width ΔR_(i12) on the bottom surface of first plane 30 andshowing several geometrical and trigonometric relationships elucidatedfrom the diagram.

FIG. 7 may be used in some embodiments to help determine the widths andtilt angles of the optical distributor's segments or faceted surfaces,which may be conical in some embodiments. The angle of incidence of theparallel rays in the downwelling beam on the i^(th) conical facet isgiven the symbol φ_(i). For specular reflection, the angle of incidencemay equal the angle of reflection, both being φ_(i). Since θ_(i) is theangle the i^(th) segment's reflected ray makes with the first plane 30and 2φ_(i) is the angle the reflected ray makes with the optical axis 5,it is known from the right triangle shown in FIG. 7 that2φ_(i)=90°−θ_(i). From the geometry of the drawing, these additionalrelationships are found for angles measured in either degrees orradians:θ_(i)=90°−2φ_(i)  (11)θ_(i)=π/2−2φ_(i)  (12)2φ_(i)=90°−θ_(i)  (13)φ_(i)=45°−θ_(i)/2  (14)θ_(i)=90°−2φ_(i)  (15)θ_(i)=π/2−2φ_(i)  (16)α_(i)=90°−φ_(i)  (17)sin θ_(i) =B _(i) /ΔR _(i12)  (18)cos φ_(i) =B _(i) /Δh _(i+1)  (19)cos φ_(i) =Δr _(i+1) /Δh _(i+1)  (20)ΔR _(i12) sin θ_(i) =B _(i)  (21)Δh _(i+1) cos φ_(i) =B _(i)  (22)Given that r_(i2) and r_(i1) are known,cos φ_(i)=(r _(i2) −r _(i1))/Δh _(i+1)  (23)Δh _(i+1) =Δr _(i+1)/cos φ_(i)  (24)ΔR _(i12) sin θ_(i) =Δh _(i+1) cos φ_(i)  (25)ΔR _(i12) =Δh _(i+1) cos φ_(i)/sin θ_(i)  (26)ΔR _(i12) =Δr _(i+1)/sin θ_(i)  (27)tan θ_(i) =y _(i1)/(R _(i1) −r _(i1))  (28)R _(i1) =r _(i1) +y _(i1)/tan θ_(i)  (29)R _(i2) =R _(i1) +ΔR _(i12)  (30)B _(i) =Δr _(i+1)  (31)

FIGS. 8A and 8B show further details of the geometry of a line segment10B inclined at an angle to the vertical, optical axis 5, used togenerate the i^(th) distributor segment or facet (by sweeping it atleast partially around the optical axis 5 to form a truncated conicalsegment) and the geometrical relationship of this line segment to acorresponding radial line segment in the target ring of width ΔR_(i12)extending from R_(i1) to R_(i2). The shaded area of FIG. 8B may indicatethe region where the downwelling incident rays 8A strike the specularlyreflecting surface of 10B and are further reflected downward and to theleft.

With reference to FIGS. 8A and 8B, two of the triangles from in FIG. 7are shown with greater detail, and from these the following additionalrelationships may be deduced:sin θ_(i) =B _(i) /ΔR _(i12)  (32)cos φ_(i) =B _(i) /Δh _(i+1)  (33)cos φ_(i) =Δr _(i+1)/Δ_(i+1)  (34)sin φ_(i) =Δy _(i+1) /Δh _(i+1)  (35)ΔR _(i12) =Δh _(i+1) cos φ_(i)/sin θ_(i)  (36)ΔR _(i12) =Δr _(i+1) cos φ_(i)/cos φ_(i) sin θ_(i)  (37)ΔR _(i12) =Δr _(i+1)/sin θ_(i)  (38)tan φ_(i) =Δy _(i+1) /Δr _(i+1)  (39)Δy _(i+1) =Δr _(i+1) tan φ_(i)  (40)180°=2φ_(i)+(90°−φ_(i))+β_(i)  (41)β_(i)=180°−2φ_(i)−90°+φ_(i)  (42)β_(i)=90°−φ_(i)  (43)

Returning to FIG. 6, the N^(th) target zone on the first plane 30 mayhave an inner radius equal to R_(N) and an outer radius R_(N+1). It alsomeans thatR _(N+1) =R _(N) +ΔR _(o)  (44)where ΔR_(o) is the equal radial widths of the target zones on the firstplane 30.ΔR _(o)=(R _(N+1) −R ₁)/N=R _(N+1) −R _(N)  (45)The inner radii of the N contiguous target zones on the first plane 30,R_(i), will be given byR _(i) =R ₁+(i−1)ΔR _(o) =R ₁+(i−1)(R _(N+1) −R ₁)/N, i=1 to N  (46)The (i−1) may be needed so that the value of the first R_(i) is R₁. Theouter radius R_(N+1) of the last zone will beR _(N+1) =R _(N) +ΔR _(o)  (47)

The conical facet angle (hypotenuse) widths Δh_(i+1) shown in FIG. 7 andtheir corresponding horizontal plane radial widthsΔr_(i)=(r_(i2)−r_(i1)) may be related to the reflected beam radialwidths ΔR_(i12) according to the equations below (some of which arelisted in the derivation sequence presented previously, Eqs. 11-43).ΔR _(i12) =Δh _(i+1) cos φ_(i)/sin θ_(i)  (48)andΔh _(i+1) =Δr _(i+1)/cos φ_(i)  (49)so thatΔR _(i12)=(r _(i2) −r _(i1))/sin θ_(i) =Δr _(i+1)/sin θ_(i)  (50)R _(i+1) =R _(i) +ΔR _(o)  (51)Also note thattan θ_(i) =y _(i1)/(R _(i1) −r _(i1))  (52)y _(i1)=(R _(i1) −r _(i1))tan θ_(i)  (53)and thatφ_(i)=π/4−θ_(i)/2=(π/2−θ_(i))/2  (54)withtan φ_(i) =Δy _(i+1) /Δr _(i+1)  (55)so thatΔy _(i+1) =Δr _(i+1) tan φ_(i)  (56)If the Δy_(i) are known, the y_(i2) can be computed fromy _(i2) =y _(i1) +Δy _(i+1)  (57)Once φ_(i) is known the widths of the reflective segments or facets maybe computed fromΔh _(i+1) =Δr _(i+1)/cos φ_(i)  (58)B _(i) =Δh _(i+1) cos φ_(i)  (59)andΔR _(i12) =Δh _(i+1) cos φ_(i)/sin θ_(i)  (60)orΔR _(i12) =Δr _(i+1)/sin θ_(i)  (61)Further,y _((i+1)1) =y _(i1) +Δy _(i+1) =y _(i1) +Δr _(i+1) tan φ₁  (62)andR _(i2) =R _(i1) +ΔR _(i12)  (63)This makes possible an iterative computation of each of the end pointsof the line segments in the r-y plane used to generate the opticaldistributor's segments or facets (which may be conical and/or reflectivein some embodiments) by sweeping the line segments 360 degrees about theoptical axis 5. In other embodiments, the line segment is only partiallyswept about the optical axis 5 and the remainder of the 360 degrees maybe left empty, filled with another distributing reflector shape, etc.

In some embodiments of the optical distributor, the diameter of the baseof the optical distributor 10 may be 24 inches and the height may beless than 24 inches, although in other embodiments the diameter may bedifferent and/or the height may be greater than 24 inches. The distancefrom the top of the optical distributor 10 to the first plane 30 mayvary, depending upon the application, the width or diameter, or theshape of the diffusely reflecting lower surface of the first plane 30may also vary. As mentioned above, in some embodiments the first plane30 may be the ceiling of a room in which the optical distributor ismounted. The optical distributor 10 may include a set of two or moresegments or faceted surfaces, 10A, 10B, 10C, 10D, etc., as described indetail above, which may be conical and/or may spread the reflected lightrays over most or all of the whole diffusing surface of the first plane30 bounded by two circles on that surface of radii R_(min) and R_(max)so that the diffusely reflected light rays reaching that portion ofsecond plane 40 which lies beneath the illuminated area of plane 30, areapproximately uniformly distributed over the second plane 40. Becausethe distributor will tend to shadow rays from plane 30 directly aboveit, preventing them from reaching plane 40, there is likely to be asignificant drop in the luminance reaching plane 40 in the area directlybeneath the distributor. Options for overcoming this are describedfurther below.

The propagation of a cylindrical beam of light rays 8A through theopening 32 in the first surface 30 onto the optical distributor 10, andthence into the reflected beam 8B of spreading rays which propagate ontothe bottom surface of the first plane 30 is illustrated in the ray tracediagram of FIG. 4. FIG. 5 approximates the results of a computerizedoptical ray tracing process applied to one embodiment of a opticaldistributor 10 wherein the rays propagating onto first plane 30 arediffusely reflected downward in FIG. 5 and onto second plane 40. Themethod described herein may provide an approximately uniformillumination of the portion of the second plane 40 below the target areaof the first plane 30 bounded by a circle of radius R₁, also designated“R_(min)” and another circle of radius R_(N+1) also designated “R_(max)”in FIG. 6.

Referring now to FIGS. 6, 7, and 8, the sizes, positions, andinclinations of the segmented portions or facets of some embodiments ofan optical distributor 10 may be determined by the process describedbelow. As mentioned above, other processes may be used in addition to orin place of the following. FIG. 6 illustrates a schematic illustrationof the way that the downwelling flux in cylindrical beam of light rays8A may be intercepted by segments or facets of the optical distributor10 and the way that this flux is reflected into multiple rings in thefirst plane 30, centered on the optical axis 5. The coordinate systemchosen is a planar Cartesian one, with coordinates r and y. The usual xcoordinate, illustrated as r in FIG. 6, is measured outward from opticalaxis 5. The vertical coordinate, illustrated as y in FIG. 6, is measuredvertically downward from the first plane 30. As shown in FIG. 6, eachline segment 10A, 10B, etc., may be used to generate a segment or facetof the optical distributor by sweeping that line segment through 360degrees of rotation (or less) about the y or optical axis 5, creating aconical segment or frustum. Other segments (such as a partially conicalsegment) may be created by sweeping the line segment through less than360 degrees of rotation. The remainder of the 360 degrees may be leftempty or filled with one or more portions of a distributor that reflectslight in different directions.

The i^(th) line segment may be defined by an inner radius r_(i1) and anouter radius r_(i2), the radial difference between these being denotedΔr_(i), with i ranging from 1 to N, where N is the number of segments inthe optical distributor, and by top and bottom y-coordinates, denotedy_(i1) and y_(i2), respectively. The vertical distance between these topand bottom y-coordinates, the vertical heights of each conical segmentor sector, is denoted by Δy_(i). Thus the end points of each linesegment are given by the Cartesian coordinates (r_(i1), y_(i1)) and(r_(i2), y_(i2)). In the design shown in FIG. 6, the end point (r_(i2),y_(i2)) of the i^(th) line segment is the start point(r_((i+1)1),y_((i+1)1)) of the (i+1)^(th) line segment. For a collimatedincident beam of light rays 8A, the rays reflected from the N conicalsegments or facets of the optical distributor may produce N rings oflight rays on the bottom surface of the first plane 30, as illustratedwith the shaded regions in FIG. 6. These rings may have inner and outerradii denoted by R_(i1) and R_(i2), respectively. The i^(th) ring ofreflected light rays having radii R_(i1) and R_(i2) on the first plane30 will propagate into the i^(th) target ring on the first plane 30having inner radius R_(i) and outer radius R_(i+1), as illustrated inFIG. 6.

The reflected rays in the i^(th) such ring may reach the first plane 30making angle θ_(i) to the first plane 30, as illustrated in FIG. 6. Eachof these rings may fall inside “target” rings on the first plane 30having inner radii R₁, R₂, R₃ . . . R_(N). The outer radius of theN^(th) ring may be R_(N+1). The radial widths of these target rings maybe the same, given by ΔR_(o). The inner radius R₁ of the first targetring may be equal to inner radius R₁₁ of the first ring of reflectedrays. This is also designated R_(min) and the outer radius of the lasttarget ring may be equal to the outer radius R_(N2). This may also bedesignated R_(max). Similarly, r₁₁ may be referred to as “R_(IN)” andr_(N2) may be referred to as “R_(OUT)”.

The mathematical relationships between the r_(i1), r_(i2), R_(i1), andR_(i2) values may be determined with reference to FIGS. 6 and 7 and theequations presented above and below. The line segment used to generatethe (i+1)^(th) segment or faceted surface is illustrated in bothfigures, but in FIG. 6 without significant angular variation from linesegment to line segment, since the figures are for illustration purposesonly. Several geometric and trigonometric relationships are shown inFIG. 7, derived from the drawing shown there, and provided in equations(11) through (61) above. The symbol n with a caret (^) over it is usedto denote a “normal vector,” a directed line that is perpendicular or“normal” to another line. On FIG. 7 the arrow with that symbol denotesthe normal or perpendicular to the i^(th) line segment used to generatethe i^(th) cone segment. The angle of incidence of a verticaldownwelling light ray incident on that cone segment may be the anglebetween the incident light ray and the normal to the cone surface at thepoint of incidence. The angle of reflection for specular or “mirror”reflection may equal the angle of incidence and is denoted φ_(i) in FIG.7.

Returning to FIG. 6, the radial distance (R_(N+1)−R_(min)) from theinner target radius R_(min) to the radius R_(N+1) or R_(max) of theouter edge of the target area on the first plane 30 to be illuminated,may be divided into N circular zones having similar radial widthsΔR _(o)=(R _(N+1) −R _(min))/N  (64)This means that the radii R_(i) are given by Equation (65):R _(i) =R _(min)+(i−1)ΔR _(o) , i=1 to N  (65)The flux to each ring may increase linearly with radius R_(i), inproportion to the area of each ring, given byA _(i)=π(R _(i+1) ² −R _(i) ²)  (66)If each ring is of the same radial width ΔR_(o), the area A_(i) of eachring may increase linearly with the inner circle circumferenceC_(i)=2πR_(i) according to Equation (67):A _(i) =πΔR _(o) ² +ΔR _(o) C _(i)=π((R _(N) −R _(min))/N)²+((R _(N) −R_(min))/N)C _(i)  (67)

The N circular bands of light reflected from the N segments or facets ofthe optical distributor may be narrower than the ΔR_(o) radial widthzones on the bottom surface of the first plane 30 upon reaching thatplane, as illustrated for example in FIG. 6. By increasing the number Nof segments or facets of the optical distributor 10 sufficiently, andwhen the incident beam of light rays has a small beam spread, the Ncircular bands of light on the first plane 30 may merge and appear moreor less continuous. In a solar lighting application, the diverging raysfrom half degree angular diameter the solar disk, combined withscattering from the first plane 30, and the use of a moderately largevalue for N may result in increased uniformity of illumination on thesecond plane 40. The value of N may in some embodiments be 4 or greater.Generally, the greater the value of N, the greater the number of targetcircular annuli of illumination on the first plane 30 and the greaterthe uniformity of the diffusely reflected flux propagating from thefirst plane 30 when it arrives at the designated area of the secondplane 40.

In some embodiments, the flux per unit area may be substantiallyconstant over a horizontal section through the downwelling cylindricalbeam of light rays 8A incident on the optical distributor 10. Eachelement of the segmented optical distributor may in some embodimentsintercept a horizontal ring of area increasing linearly, i.e.proportional to A_(i) as calculated in (67). These two conditions mayenable the average irradiance or illuminance across the illuminatedportion of the first plane 30 to be made substantially constant for eachzone.

To achieve this goal, Δr_(i) may be made to be proportional to (i−1) sothat it will increase linearly with i as follows:Δr _(i) =K(i−1)  (68)with K being the constant of proportionality, obtained by summingequation 68 over all values of i from 1 to N+1 and then solving for K,and setting the result equal to R_(OUT)−R_(IN). Using (68), thiscondition is expressed as follows:

$\begin{matrix}{{K{\sum\limits_{i = 1}^{N + 1}\;\left( {i - 1} \right)}} = {R_{OUT} - R_{IN}}} & (69)\end{matrix}$In evaluating this summation, we use the sum of integers function:SumOfIntegers(n)=1+2+3+ . . . +n=(n ² +n)/2  (70)expressed as

$\begin{matrix}{{\sum\limits_{i = 1}^{N}\;(i)} = \frac{N\left( {N + 1} \right)}{2}} & (71)\end{matrix}$so that also

$\begin{matrix}{{\sum\limits_{i = 1}^{N}\;\left( {i - 1} \right)} = \frac{N\left( {N - 1} \right)}{2}} & (72)\end{matrix}$and also

$\begin{matrix}{{\sum\limits_{i = 1}^{N + 1}\;\left( {i - 1} \right)} = {\frac{N\left( {N + 1} \right)}{2}.}} & (73)\end{matrix}$Using these, solving (69) for K results in the formula of equation 74results in

$\begin{matrix}{K = {\frac{2\left( {R_{OUT} - R_{IN}} \right)}{N\left( {N + 1} \right)}.}} & (74)\end{matrix}$Thus, given R_(IN) and R_(OUT), the desired inner and outer radii of thesegments or facets of the optical distributor, the radial boundaries ofeach segment or facet, may be given by the formulae:r ₁₁ =R _(IN)  (75)r _(i1) =r _((i−1),2) for i=2 to N+1  (76)Δr _(i) =K(i−1) for each I  (77)andr _(i2) =r _(i1) +Δr _(i+1)  (78)for each i. These equations may in some embodiments ensure that eachdistributor segment or faceted surface will intercept an increasingquantity of flux in the downwelling beam, which increase may be linearwith respect to i, thereby making the flux received in each target zoneon first plane 30, divided by the area of that zone, approximately thesame for all target zones on first plane 30.

To generate the y_(i1) and y_(i2) values from the above requirements,the trigonometric relationships developed in FIG. 7 and provided inequations (11) through (82) may be used. The i^(th) distributor linesegment width is the hypotenuse Δh_(i+1) of the right triangle havingopposing sides of lengths Δr_(i+1) and Δy_(i+1), this hypotenuse havinglength equal to the square root of the sum of the squares of Δr_(i+1)and Δy_(i+1), as illustrated in FIG. 8A. The downwelling rays onto theupper and lower ends of this line segment, due to the law of reflection,may be reflected through angle 2φ_(i) up onto the first plane 30 atradii R_(i1) and R_(i2), respectively, as illustrated in FIG. 8A. Usingthe trigonometric derivations provided above, and since R₁₁ (=R_(min))and y₁₁ may be set by the designer, and sincetan θ₁ =y ₁₁ /R ₁₁  (79)and since2φ_(i)==90°−θ_(i)  (80)for all values of i, and since we may know φ₁, we may thereforecalculateΔh ₂=(r ₁₂ −r ₁₁)/cos φ₁  (81)From this we obtain Δy₂ and from this we may also know thaty ₁₂ =y ₁₁ +Δy ₂  (82)Once we know these parameters we may then use the equation derived inFIG. 7 forΔR _(i12) =Δr _(i+1)/sin θ_(i)  (83)to obtainR _(i2) ==R _(i1) +ΔR _(i12)  (84)And so we have mapped (r₁₁, y₁₁) and (r₁₂, y₁₂) to R₁₁ and R₁₂, using(71) for r₁₁, (77) for Δr_(i), (78) for r_(i2) (82) for y₁₂, (84) forR₁₂, and with R₁₁ (=R₁=R_(min)) and y₁₁ being set by a designer. Thesame process may be used to determine the coordinates of the remainingline segment end points.In general, we have from FIGS. 6, 7, and 8:Δh _(i+1) =Δr _(i+1)/cos φ_(i)  (83)Tan φ_(i) =Δy _(i+1) /Δr _(i+1)  (84)R _(i1) =r _(i1) +y _(i1)/tan θ_(i)  (85)R _(i2) =R _(i1) +ΔR _(i12)  (86)and so forth. The method used to design the reflective opticaldistributor 10 may include calculating the top and bottom coordinates ofeach segment or facet of the optical distributor, starting at the topand sequencing downward in an iterative manner to the bottommost one insome embodiments. At each step, we may also calculate the start R_(i1)and end R_(i2) radii of the reflected beams on the first plane 30. Theequations provided above may be used to determine each θ_(i), φ_(i), andα_(i).

The slope angles β_(i) of each line segment relative to the optical axis5 may be computed with the aid of FIG. 8B, yieldingβ_(i)=90°−φ_(i)  (87)For aesthetic or improved performance reasons, once the contiguoussegments or facets have been determined by the above sequence, thevertical spacing between them may be increased from 0 to any other valueΔy, but the positions of the start and end points of the segments ofwidth Δh_(i+1) used to generate the faceted distributor must berecalculated with the new values for y_(i1) in the above sequence ofcoordinate calculations, for the target zones on plane 30 to remain inthe same locations. Without such recalculation, the spacing of thetarget zones of radial widths ΔR_(i12) will increase somewhat as thevertical spacing Δy of the distributor faceted reflectors increases.

FIG. 9 shows a bottom plan view of the bottom surface of the first plane30 including the ray intersection locations as small dots. FIG. 9 showsthat, in the case of perfectly collimated incident rays 8, the reflectedrays from segments or facets 10A, 10B, 10C, and 10D of a four-facetedoptical distributor 10 (i.e., N=4) propagate to zones 60A, 60B, 60C, and60D, respectively, on the first plane 30, as shown by the ray tracegenerated by optical ray tracing software. This ray intersection (or“spot”) diagram of the bottom surface of the first plane 30 illustratesthat the number of rays may increase with the radius of each annularzone when the optical distributor is designed according to the methoddescribed above. When the rays incident on the first plane 30 arereflected diffusely onto the second plane 40, the distribution of fluxacross the second plane 40 may be greatest on the second pane 40 at aradius slightly greater than the center radius of the target zone givenby R_(ceilMin)+(R_(ceilMax)−R_(ceilMin))/2.

If the distance between planes 30 and 40 is several times greater thanthe distance from plane 30 to the bottom of the distributor, a portionof the flux diffusely reflected from the first zone (60A in FIG. 9), andto a decreasing extent from the remaining plane 30 zones, will tend tofill in some of the shadow produced by the distributor. By increasingthe number of faceted sections or segments of the optical distributor10, by sizing and angling them using the procedure described herein, bymaking the inner radius R_(IN) of the first distributor segmentedreflector nonzero, and by placing a lens in the resulting opening ofradius R_(IN) at the top of the optical distributor and/or placing atranslucent diffusing sheet at the bottom of the optical distributor toreceive and diffusely transmit the flux from the hole at the top of thedistributor, the luminance distribution across the second plane 40 maybe made more uniform. In other embodiments, one or more of thesetechniques may be used alone, and/or one or more of these techniques maybe modified and/or used in combination.

FIGS. 10A and 10B illustrate an embodiment of an optical distributor 10with glare shields 70, which may in some embodiments help preventscattered light rays from entering into the eyes of occupants of a roomwhere an optical distributor 10 is installed. FIG. 10A shows a side planview of several shallow conical glare shields 70 coupled to the opticaldistributor 10. The shallow conical glare shields 70 may be fabricatedas truncated, opaque cones surrounding the faceted optical distributor10 and inclined upward and outward at, in some embodiments, the same (ornearly the same) angles as rays reflected from the optical distributor10. The glare shields 70 may help prevent an optical distributor fromsending stray light scattered from the surface of the distributor 10 outof the reflected beam and away from the first plane 30. This effect isgreatest when second plane 40 is spaced below the first plane 30 onlyone to a few times greater than the distance between the bottom ofdistributor 10 and plane 30. In such cases, the glare stack may prove tobe helpful in reducing or eliminating glare from distributor 10 diffusereflections. The effect is least when the second plane 40 is many timeslower from plane 30 than is the bottom of the distributor, in which casethe glare shield stack may not be needed. The stack of glare shields 70in FIG. 10A may be vertically aligned and may allow the specularlyreflected light rays from the optical distributor 10 to pass relativelyunimpeded between the conical surfaces, hence blocking little or no fluxspecularly reflected from distributor 10 to first plane 30. The stack ofglare shields 70 may also block light rays scattered out of thespecularly reflected flux beam by, for example, imperfections in thesurface finish of the optical distributor 10, or by accumulated dust anddirt on the optical distributor 10. The stack of glare shields 70 maythus keep “stray” scattered light rays from propagating downward andradially outward below the bottom of the optical distributor where itmight otherwise produce stray light rays or a glare condition.

The bottom surfaces of each glare shield may in some embodimentssubstantially absorb the light impinging on them and/or may diffuselyreflect the light scattered from them. The top surfaces may be specularor diffusely reflective, in order to, for example, send light incidentupon them outward and upward to the first plane 30. If imperfections inthe fabrication of such a glare shield stack cause the top surfaces ofthese shallow cones to receive some of the bright, specularly reflectedlight from the optical distributor, such surfaces may be given a darkand absorbing finish, thereby helping block such light from reflectingup to the glare shield above it and thence back down into the eyes ofoccupants of the illuminated space below. The top such glare shield mayin some embodiments, however, be given a specular or diffuselyreflecting finish in order to send at least some of the light incidentupon it up onto the first plane 30. Each glare shield in the stack mayhave an inner radius r_(in) (which may be equal to the outer radius ROUTof the base of the optical distributor as in FIG. 6) and an outer radiusr_(out).

FIG. 10B shows an isometric view of the glare shields 70 with the innerradii of the glare shields equal to or greater than the radius of thebase 20 of the optical distributor 10 and the outer radii chosen toblock glare due to light scattered from the optical distributor 10.

In some applications, the first plane 30 (e.g., the ceiling) may be farenough above the second plane 40 (e.g., the task plane) that the anglebetween the specularly reflected light rays 8B to the first plane 30 andthe rays scattered from the optical distributor 10 down and radiallyoutward to the eyes of persons standing or seated in the space below maybe fairly large, such as, for example, greater than 10 to 20 degrees. Atsuch angles of scattering, the strength of the scattered light may below, may not produce a serious stray light or glare condition, and,consequently, the glare shield stack may not be needed, although inother embodiments, one or more glare shields may still be used.

FIGS. 11A and 11B illustrate various angles and dimensions which may beused in computing the angles and dimensions of the glare shields 70. Asshown in these figures, the vertical rise of a glare shield cone Δy_(b)may be chosen to match the angle θ_(i) of the nearest rays reflectedfrom the optical distributor cone 10 upward and outward toward the firstplane 30. Letting Δr=r_(out)−r_(in), the value of Δy_(b) is given byΔy _(b) =Δr tan θ_(i)  (88)

The vertical distance Δy_(a) from the top of one glare shield cone tothe bottom of the next one above it may be set by the glare blockageangle α shown in FIGS. 11A and 11B. Let R be the radial distance in ahorizontal plane from the center of the glare shield stack and opticalaxis 5 to an observer whose eye 71 is no less than distance (H1+H2)below the first plane 30. Let α be the glare edge angle, e.g., the angleof a line from the horizontal below which the optical distributor 10 isnot visible between the glare shields 70. If the distance (H1+H2) of ahuman's eyes 71 below the first plane 30 and the radial distance R fromthe center are the maximum distances of concern for glare to be visibleby the observer, and further if H1 is the distance from the first plane30 down to the top of the glare shield 70 of interest, then the value ofangle α above which scattered light from the optical distributor 10between the two glare shields is just visible may be given byα=arctan(H2/R)  (89)

From the geometry of the space being illuminated, a designer may be ableto determine a maximum value of R and may also be able to determine thedistance H1 from the first plane 30 down to the outer edge of the glareshield of the calculation (repeated for each of the glare shields). Thedesigner may also choose a representative maximum distance of anobserver's eyes 71 above the second plane 40 and down from the firstplane 30 of the space for avoiding a glare condition, therebydetermining the value of H2, thereby also setting, through the use of(89), a value for the angle α. To avoid these multiple repeatedcalculations for each of the glare shields, one possible alternative mayinclude setting the bottom of the optical distributor to be well abovethe maximum height of human eyes 71 in the space, so one can set H2 andhence also angle α equal to zero. For this case one may set the bottomof a glare shield to be at the same vertical distance below the firstplane 30 that is the top of the next glare shield 70 below it. Theradial width Δr of the glare shield 70 stack in such case may bedetermined by the vertical height h of the optical distributor 10 andthe number of glare shields desired. The overall radius from the opticalaxis 5 of the glare shield stack will equal r_(out)=r_(in)+Δr, asillustrated in FIG. 11A and the stack diameter will be given by2r_(out).

FIG. 12 illustrates a low-profile embodiment of an optical distributor,wherein a top portion 11A and 11B of the faceted conical distributor isreplaced by a concave faceted conical interior section with each newfacet 11A and 11B having separately calculated sizes and slopes in someembodiments. This “crater-like” interior reflecting surface may becalled the “cross-fire” section because rays reflected from it may crossthrough a focal line coincident with the optical axis and emerge fromthe “crater” on the opposite side, continuing to propagate up and outonto the first plane 30 without being reflected further by the opticaldistributor.

The low-profile version of such an optical distributor may have areduced overall vertical height, allowing it to be placed closer to thefirst plane 30. In this embodiment, a top portion of the opticaldistributor may be replaced with a faceted conical reflector that isinverted (i.e., is concave), and may descend inside the center of theunaltered remainder of the design, like a crater, which concavereflecting portion may reflect incident light in the downwellingincident beam out of the “crater” without further reflection from anypart of the conical reflector. The optical distributor shown in FIG. 12may have a reduced vertical profile and may allow the visible surface ofthe optical distributor to be reduced, which may further reduce glareassociated with diffusely reflected beams from dust or other effectsand/or reduce the number and size of glare prevention shields.

Another, similar alternate embodiment truncates a portion of the concave“crater” surface descending inside the main outer surface and replacesthe removed section with a modified replica of the top of the removedportion of the original faceted optical distributor (i.e. afrustum-shaped insert), this design resulting in the optical distributorshown in FIG. 19 and described below.

Returning to FIG. 12, the top of an optical distributor designed by theabove method may be truncated and the removed section replaced by aconcave interior reflective zone, somewhat like the crater of a volcano.This may be done in order to create a lower-profile optical distributor,enabling the placement of this optical element closer to the first plane30 (as might be used in low-bay or low ceiling height solar illuminationand other applications). However, in this embodiment of an opticaldistributor, it still may be useful in some instances to reflect as manyrays as possible from the added “crater” or “crossfire” element up andout of the “crater” without allowing them to intersect the opposite edgeof the added concave cone and still send such rays as far radiallyoutward as possible, so that they do not, for example, propagate upthrough the opening 32 in the first plane 30.

FIGS. 13 through 16 show schematic diagrams of portions of a radialoptical distributor with various geometrical lines, dimensions, andangles illustrated for use in explaining various mathematical steps thatmay be used in some embodiments to compute potential dimensions of someembodiments of an optical distributor. FIG. 13 is a schematic diagram ofa cross-section of the concave portion of the truncated, low profileversion of an optical distributor, detailing three interior segments ofdistributor 10 and the angles of inclination and inner and outer radiiof each segment or facet. FIG. 14 is a schematic diagram showing thei^(th) line segment of the crossfire section of the low-profiledistributor, and the end point coordinates. FIG. 15 is also a schematicdiagram showing an alternate geometrical diagram in support of thecrossfire design method, and shows relevant angles α_(i) and φ_(i) andtheir relationships to the vertical y and horizontal r dimensions of theconcave crossfire or “crater” section of the optical distributor. FIG.16 is also a schematic diagram, and may be used to isolate the M^(th)line segment, the first one of the crater, and use the geometry of it todetermine the value of y_(M+1) based on Δr.

With reference now to FIGS. 12 through 16, a four segment opticaldistributor may be designed. The method of designing this distributormay begin by generating an optical distributor as explained above, withN segments. A designer may then determine how many of the top segmentsto remove and replace with the concave “crossfire” or crater section.Let the segments to be removed number 1 to M, counting from the topdownward, with M being less than N. The replacement crater section maybegin at the top edge of the (M+1)^(st) segment (which remains in place)and descend inward and downward into the interior of the truncateddistributor, counting backward from M to 1. In order for the innermostcrater line segment, number 1, to terminate at the design radius ofR_(IN), the radial widths of line segments 1 through M may all be thesame. The crater section line segments may therefore each have radialwidth Δr given by Eq. 90.Δr=(r _(M2) −R _(IN))/M=(r _((M+1)1) −R _(IN))/M  (90)

With reference to FIG. 13, the figure illustrates that the lowest (solidline) rays from the bottom of each conical facet may converge to the topof the opposite “crater edge” and then diverge upward and radiallyoutward from there; (dashed line) rays from the top of each conicalfacet converge to a position in space above the “crater” and thencediverge upward and radially outward from it, which may be onto the firstplane 30 and not back up and through the opening 32.

In some embodiments, the start and end points of the crossfire cratersegments are designed so that all rays reflected from each of them clearthe top edge of the opposite crater rim, as illustrated in FIGS. 13 and15. For these crossfire calculations, the y-coordinates are measureddifferently than for the main distributor derivation, from the base 20of the untruncated distributor, designed using the procedure describedabove, upward to the highest point of the new truncated distributor, aty=y_(M+1), as illustrated in FIG. 13. Using this new coordinateconvention, each line segment, with end point coordinates (r_(i1),y_(i)) and (r_(i2), y_(i+1)), may obey the right triangle relationshipsshown in the sketch in FIGS. 13, 14, and 15:Tan φ_(i)=(y _(i+1) −y _(i))/(r _(i2) −r _(i1))=Δy _(i) /Δr  (91)Tan α_(i)=(y _(M+1) −y _(i))/(r _(M2) −r _(i1))  (92)where angles α, and φ_(i) are as illustrated in the drawing of FIGS. 13and 15. Equation (92) is the crossfire clearance condition, rewrittenas:

$\begin{matrix}{{\tan\;\alpha_{i}} = {\frac{y_{M + 1} - y_{i}}{r_{M\; 2} + r_{i\; 1}}.}} & (92)\end{matrix}$From FIG. 15 we know thatα_(i)=90°−2φ_(i)  (93)and from FIG. 14 we see thatΔy _(i) =y _(i+1) −y _(i)  (94)Next we use (92) and (93) to write φ_(i) as a function of y_(M+1) (equalto y_(M2)), r_(M2), y_(i), and r_(i1):φ_(i)={90°−tan⁻¹[(y _(M+1) −y _(i))/(r _(M2) +r _(i1))]}/2  (95)

From FIG. 16, the tilt angle of the M^(th) mirror facet up from thehorizontal is φ_(M) and Δr is the same for all crater line segments andis given by (90). Since φ_(i) is given by (95), we can determine y_(i)from (91)y _(i) =y _(i+1) −Δr tan φ_(i)  (96)but to get φ_(i) from (95) we may need to know y_(i+1) and y_(i). Thevalue of y_(M+1) may already be known, since it may be part of theoriginal untruncated distributor.

FIG. 16 isolates the Mth line segment and the ray from its bottom end tothe top rim of the crater opposite this line segment. Using (92)

$\begin{matrix}{{\tan\;\alpha_{M}} = {\frac{y_{M + 1} - y_{M}}{r_{M\; 2} + r_{M\; 1}} = \frac{\Delta\; y_{M}}{r_{M\; 2} + r_{M\; 1}}}} & (92)\end{matrix}$and noting that

$\begin{matrix}{{{\tan\;\phi_{M}} = \frac{\Delta\; y_{M}}{\Delta\; r}},} & (97)\end{matrix}$one can solve (97) for Δy_(M) and substitute the solution into (92) toarrive at the following equation for determining α_(M) from knownparameters:

$\begin{matrix}{{\tan\;\alpha_{M}} = {\frac{\Delta\; r\;\tan\;\varphi_{M}}{\left( {r_{M\; 2} + r_{M\; 1}} \right)}.}} & (98)\end{matrix}$Replacing α_(M) in (98) with its equal, (90°−2φ_(M)) from (93), twoequations in two unknowns (y_(M) and φ_(M)) result:tan(90°−2φ_(M))=Δr tan φ_(M)/(r _(M2) +r _(M1))  (99)tan φ_(M) =Δy _(M) /Δr=(y _(M+1) −y _(M))/(r _(M2) −r _(M1))  (100)Three useful trigonometric identities aretan(90−u)=cot u  (101)cot 2u=(1−tan² u)/2 tan u  (102)tan 2u=2 tan u/(1−tan² u)  (103)so that (99) can be written and transformed as follows:cot 2φ_(M) =Δr tan φ_(M)/(r _(M2) +r _(M1))(1−tan²φ_(M))/(2 tan φ_(M))=Δr tan φ_(M)/(r _(M2) +r _(M1))(r _(M2) +r _(M1))(1−tan²φ_(M))=2Δr tan²φ_(M)(r _(M2) +r _(M1))−(r _(M2) +r _(M1))tan²φ_(M)=2Δr tan²φ_(M)(2Δr+r _(M2) +r _(M1))tan²φ_(M) =r _(M2) +r _(M1)  (104)Which is solved for

$\begin{matrix}{{\tan^{2}\phi_{M}} = \frac{r_{M\; 2} + r_{M\; 1}}{{2\Delta\; r} + r_{M\; 2} + r_{M\; 1}}} & (105) \\{{\tan\;\phi_{M}} = {\sqrt{\frac{r_{M\; 2} + r_{M\; 1}}{{2\Delta\; r} + r_{M\; 2} + r_{M\; 1}}}.}} & (106)\end{matrix}$Solving (100) for Δy_(M) yieldsΔy _(M) =Δr tan φ_(M)  (107)so thaty _(M) =y _(M+1) −Δy _(M) −y _(M+1) −Δr tan φ_(M)  (108)

Since φ_(M) and y_(M) may be known, the foregoing illustrates onepossible procedure for calculating the coordinates of the inner (andlower) end of the first crossfire crater line segment, the M^(th) one,and then using the same approach to determine the i=(M−1)^(th) one andthe remaining ones down to i=1. Other procedures may also be used inaddition to or in place of the foregoing.

The compacted iteration sequence described above may therefore be asfollows. Start with the known value of Δr:Δr=(r _(M2) −R _(IN))/M=(r _((M+1)1) −R _(IN))/M  (109)and y_(M+1) being known from the (M+1)^(st) regular cone bottom y-value,corrected for the new convention on the y coordinates for the crossfiresection. LetB=(r _(M2) +r _(M1))  (110)calculatetan φ_(M) =[B/(2Δr+B)]^(1/2) and  (111)φ_(M)=arctan [B/(2Δr+B)]^(1/2)  (112)and then calculateΔy _(M) =Δr tan φ_(M) and  (113)y _(M) =y _(M+1) −Δy _(M) =y _(M+1) −Δr tan φ_(M)  (114)Then begin a looped iterative calculation sequence from i=M−1 countingdown to i=1, and at each value of i, do the following calculationsequence. (Note that Δr, y_(M), y_(M+1), φ_(M) and Δy_(M) are known fromabove.) LetB=(r _(M2) +r _((i)1))  (115)then calculatetan φ_(i) =[B/(2Δr+B)]^(1/2)  (116)Δy _(i) =y _(M+1) −B tan φ_(i)  (117)y _(i) =y _(M+1) −Δy _(i)  (118)until i−1=1. Once the end points of the main cone and the replacementsegments making up the crossfire crater have been calculated and used todraw the line segments, the set of line segments may be spun (extrudedor swept) through 360 degrees around the vertical optical axis 5 tocreate the three-dimensional distributor having a low-profile crossfirecrater section.

FIG. 17 shows isometric views of a wire-frame design of a low-profileoptical distributor designed according to the above description. Amoderately large value for N was used and the crossfire distributorshape was calculated for a representative set of initial design values.

The optical distributor embodiment illustrated in FIG. 17 has twosections, and as described below, another embodiment may have threesections (see FIG. 19). These embodiments with multiple surfaces mayreduce the height profile of the optical distributor while stillmaintaining approximately the same reflection as in the embodiment shownin FIG. 1. This may be done in order to place the optical distributorcloser to the first plane 30 so that the optical distributor does notextend as far down into the space below that plane. This low-profiledesign may be useful in a variety of locations, including use in, forexample, “low bay” building spaces having ceiling heights lower than 12feet above the floor. Another purpose may be to reduce the area of theoptical distributor visible from the side (thereby reducing the amountof glare-producing flux that could be scattered out and thereby alsoreducing the number and sizes of any glare shields that might beneeded).

By increasing the number N of line segments used to generate thereflective distributor shown in FIG. 17 and by fitting a smooth curve tothe end points of those line segments, a smooth curve may be producedthat may have the same inner and outer radial positions R_(IN) andR_(OUT) and the same height and vertical position as the segmenteddistributor. The result may be similar, especially if N is equal to 20or more, and may produce a smoother distribution of flux across thetarget area of the first plane 30. Fitting a typical design to aquadratic equation and to a trigonometric equation may produceacceptable results (as illustrated in FIG. 17 for the crossfire craterembodiment).

FIG. 18 illustrates a side plan view of the results of a computerizedoptical ray trace of the crossfire section of the low-profiledistributor design of FIG. 17. In FIG. 18, the incident parallel lightrays 8A are confined to a reduced width vertical plane (for the purposesof this illustration only) may enter the “crater” crossfire section andmay be reflected up and out over the opposite lip of the crater sectionand thence onto the first plane 30 as light rays 8B. Incident rayspassing through an opening 34 in the bottom of the crater may in someembodiments reach an optical diffusing sheet 26 (as shown, for example,in FIGS. 18 and 30) and may be scattered by it laterally into the spacebelow as light rays 8C as illustrated in FIG. 18.

FIG. 19 is a cross-section view of another alternate, exemplary,embodiment of an optical distributor whereby the concave interiorfaceted conical “crater” sections 12C, 12D, and 12E (three in number forthis illustration) of an optical distributor contain inside them atwo-segment (for this illustration) convex interior reflector portion12A and 12B. In order to create a still lower-profile opticaldistributor, enabling the placement of it closer to first plane 30 inlow-bay solar illumination and other applications, the crossfire or“crater” portion of the embodiment shown in FIG. 17 may itself betruncated and replaced by a new set of segments similar to the first fewline segments of the original untruncated distributor design asillustrated by the cross-section view in FIG. 19. The convex mini conein the center has new line segments 12A and 12B, which are designed tobe shallower than the original untruncated distributor top, so as tohelp make sure the reflected rays propagate up and out of the centralconcave crater section. The revised cross-fire section has segments orfacets 12C, 12D, and 12E in the design shown schematically in FIG. 119.The main portion of the optical distributor has segments 12F and 12G.When these are swept through 360 degrees about the vertical optical axis5, the result may be a three-dimensional faceted optical distributor. Across-section of this object in a vertical plane containing the opticalaxis 5 is illustrated in FIG. 19.

FIG. 20 illustrates another embodiment of an optical distributor. Theoptical distributor shown in FIG. 20 may include several planar orslightly curved segments or facets 13A, 13B, 13C, 13D, 13E, etc., eachsending its reflected light radially outward and/or upward towardsseveral different target areas to be illuminated. The opticaldistributor shown in FIG. 20 may also redirect and slightly spreadmultiple portions of the light from a cylindrical collimated beam ontoone or more selected areas of either the first or the second planes 30,40 described above, and/or onto vertical planes or other areas in orderto, for example, illuminate or irradiate all or selected portions ofthese areas with relatively high irradiance or illuminance.

The optical distributor shown in FIG. 20 may be a more generallyfaceted, approximately conical, configuration that may send mini-beamsof directed illumination in different directions across the space belowthe first plane 30. The optical distributor may include severalindividual triangular and/or approximately trapezoidal or otherpolygonal shaped facets arranged around the nominally conical envelope.Each facet may reflect a mini-beam of light upward and outward into thespace. Each facet may be planar, cylindrical, spherical, convex,concave, etc., in surface shape, or they may be more generally curved tosuit a number of planned and specialized targeting directions.

FIG. 21 illustrates another embodiment of an optical distributor 10,with the optical distributor 10 including, directly beneath a hole oraperture 34 in the center of its top, a single specularly or diffuselyreflective reflector 50 having an elliptical perimeter, the surface ofwhich is planar, convex, or concave shaped, and which reflects thecollimated incident beam of light rays 8A that passes through theopening 34 in the center of the optical distributor 10 radially outwardand upward, downward, or laterally in either a slightly spreading orslightly converging manner toward a targeted task area to beilluminated. Vertically incident light rays 8A reflect from reflector 50and may then propagate as reflected light rays 8B.

In some embodiments two independently targetable reflectors may be madeby cutting reflector 50 along a horizontal line through its center,rotating the upper half about the cut line and thereby sending thereflected light rays in two separate directions, approximately oppositeeach other. This distributor design may be useful, for example, inilluminating the ceiling of a narrow aisle or corridor from adistributor at one end of that corridor or from the center of thecorridor using the rooftop configuration. This embodiment, known hereinas a linear optical distributor design, to distinguish it from theprevious radial designs, may also be used for large area illumination,wherein multiple incident beams and distributors are placed side-by-sideto cover a large area, essentially as if that area were composed ofmultiple long aisles to be illuminated.

The optical distributor illustrated in FIG. 21, multiples of thisdesign, or multiple “split” embodiments producing two or more reflectedbeams may also be used to spread one or more portions of the incidentcollimated beam 8A in a controlled manner to send the reflected beam orbeams toward one or several specified directions, such as for tasklighting, or to illuminate one or more portions of one or more walls ofa room for various purposes, rather than reflect it up onto the firstplane 30 (e.g., a ceiling) or other horizontal diffusely reflectingsurface. The version of this embodiment depicted in FIG. 21, illustratesa collimated cylindrical downwelling beam of light rays 8A passingthrough a circular or polygonal opening 34 in the optical distributor 10and onto a specularly reflecting elliptical perimeter reflector 50 whichmay be planar, cylindrical, spherical, or with a more complex surfaceshape. FIG. 21 depicts a slightly convex design, so that the reflectedrays 8B diverge slightly from being parallel as they propagate away fromreflector 50 and toward a target area, which may be a task area in needof stronger illumination for fine or precision work, or may be an areaneeding some solar heating for thermal processing purposes.

Still another embodiment, as described below, may include multiplereflectors each having perimeter shapes that are elliptical, sections ofan ellipse, circular, or polygonal, thereby compacting the reflectorsand offering the possibility of aiming each one in a different orsimilar direction to send the light rays toward one or more targets inthe space. FIG. 20 is one example of this embodiment of an opticaldistributor.

FIG. 22 shows another example of a multiple reflector embodiment of anoptical distributor. In FIG. 22, the single reflector 50 shown in FIG.21 is replaced with two or more reflectors 50, each relatively parallelto each other or not, each having perimeter shapes that are elliptical,sections of an ellipse, circular, or polygonal. The multiple reflectorsof the optical distributor shown in FIG. 22 may allow the flexibility ofaiming each reflector in a different direction to send the light raystoward multiple targets.

FIG. 23 shows another multiple reflector embodiment of an opticaldistributor, in which the rectangular reflectors 50 of the opticaldistributor shown in FIG. 22 are replaced by elliptical reflectors 50,with the elliptical reflectors also angled differently.

FIGS. 24A and 24B show isometric views of still yet other embodiments ofan optical distributor. The optical distributor shown in FIGS. 24A and24B may generally be a pyramidal shape. This embodiment of the opticaldistributor may be used, for example, in implementations needing lightsent in two or four orthogonal opposing directions. Two opposite facesof the pyramid are larger and angled differently than the orthogonalones. In this manner the larger faces may send more light, and send thelight further into an elongated space while the smaller orthogonal onessend less light into a narrower portion of the illuminated space, suchas the intersection of perpendicular short and long hallways in abuilding. These faces may be segmented or curved, but are designedaccording to the general principles described above in order, forexample, to illuminate the first plane 30 more fully and in a relativelyuniform manner.

FIG. 24B illustrates a more curved version of the optical distributorshown in FIG. 24A. The four side surfaces (or faceted surfaces) of theoptical distributor shown in FIG. 24B may be curved or convex in order,for example, to control the reflected light rays better, and/or tospread a reflected beam over the first plane 30 and possibly the wallsof the illuminated space in some embodiments. The optical distributorsshown in FIGS. 24A and 24B may be used to illuminate spaces on eitherside of a wall separating those spaces, as shown and described belowwith reference to FIGS. 25 and 26.

FIG. 25 shows an isometric view of an implementation of the curvedpyramid design of FIG. 24B in a slot 53 in a wall 51 between two rooms.In this case, a pyramidal shaped optical distributor is placed in a slot53 at the top of the wall between the two spaces, so that some of thelight 8A coming through the opening 32 in the ceiling plane 30 may bereflected and spread across the ceilings and walls of the two spaces oneither side of the separating wall 51. If the wall does not extend allthe way from the floor to the ceiling, then the narrow ends of thepyramid distributor shown in FIG. 24B may be used to illuminate theceiling above the wall. Otherwise, these narrow ends of the opticaldistributor may be small or nonexistent, in order to send most of thelight reflected from the optical distributor into the two spaces oneither side of the wall.

FIG. 26 shows a top plan view of an implementation of the curved pyramidoptical distributor of FIG. 24B, similar to that shown in FIG. 25 exceptthat the optical distributor in FIG. 26 may be used to illuminate fourdifferent rooms instead of only two. The optical distributor 98 in FIG.26 may be a square pyramidal shape (i.e. with four sides that areapproximately the same width) and may be placed in a slot at the top offour intersecting walls. The opening 32 in the first plane 30 throughwhich the downwelling collimated beam passes may be placed in the commoncorner of the four adjacent rooms and the approximately equal-sidedoptical distributor may be placed in a slot 97 where the four rooms cometogether in a common corner. The optical distributor may be positionedsimilarly to the schematic illustrated in FIG. 25, except that the foursides of the optical distributor may face toward the centers of each ofthe four rooms and the curvatures of these four sides may be adjusted tosend the reflected light upward and radially outward onto the ceilingsof those rooms, as illustrated with the dashed line arrows 8B simulatingreflected light rays in FIG. 26. This design may be thought of as ahybrid of several other embodiments of optical distributors, such as theoptical distributor 10 in FIG. 1 and the optical distributor 100 in FIG.37. If the four rooms being illuminated by the design in FIG. 26 aredifferently sized, each quadrant of the distributor 98 may be designedslightly differently, to optimize the light distribution in each room.

FIG. 27 shows an isometric view of cylindrical light pipes 80 that maybe used in conjunction with an optical distributor composed of fourtrapezoidal perimeter planar reflectors arranged in a pyramidal shape, apyramidal frustum. The light pipes shown in FIG. 27 may be cylindricaland specularly or diffusely reflective in some embodiments, and mayreceive light rays reflected from the optical distributor (which may be,for example, the pyramidal optical distributor shown in FIG. 24A havingfour planar faces) and transport the received light rays through thelight pipes shown to somewhat remote areas where the light rays may beextracted and/or distributed to illuminate a task area or space. In FIG.27, the incident light rays 8A are reflected from the four facets of thepyramidal distributor and propagate into and through the light pipes 80.In other embodiments, the cylindrical light pipes 80 may be replaced bylight pipes having elliptical, rectangular, trapezoidal, or othercross-sectional shapes.

The light pipes 80 may in some embodiments be large enough to accept allthe light rays reflected from a face of the optical distributor and/orlarge enough to minimize the number of reflections from the light pipe'sinterior surface. In some of such embodiments, the interiors may not bereflective, in which case the light pipes mainly serve to protect thepossibly concentrated beams propagating within them. Although FIG. 27shows the light rays being distributed into four light pipes 80, more orfewer light pipes 80 may be used in other embodiments. For example, bymaking two opposite sides of the distributor very small, most of thelight rays incident on the other two sides of the optical distributormay be directed into two oppositely directed light pipes.

FIG. 28 shows an isometric view of cylindrical light pipes similar toFIG. 27, except that a different optical distributor is used in FIG. 28,one with planar elliptical perimeter faces replacing the trapezoidalperimeter ones in FIG. 27. The light pipes in FIG. 28 may receive lightrays reflected from the four planar elliptical reflectors and transportthe received light rays to somewhat remote areas where the piped lightrays are extracted and further distributed as desired. The light rayspassing downward between the elliptical reflectors may be furtherdistributed into the space below by means of a translucent diffusingsheet to spread the downward propagating beam, optical distributorssimilar to those described above, or through the use of Fresnel lenssheets to spread the rays passing between the elliptical reflectors thatare not reflected by them.

FIGS. 29A through 29C illustrate the use of three different opticalassembly designs, to redirect the quasi-collimated light rays 8Demerging from the light pipes 80 shown in FIGS. 27 and 28 in order tospread that light in a controlled manner as diverging rays 8E into aparticular space.

The optical assembly designs illustrated in FIGS. 29A through C may bereflective and/or transmissive luminaries and may receive light rays 8Demanating from light pipes 80, redirect that light downward or laterallyby means of a convex specular-only or a combination of specular anddiffuse elliptical reflector 91, and into the space below, asillustrated in FIG. 29A. The optical assembly designs may redirect thelight downward by means of an elliptical planar specular reflector 93 asillustrated in FIG. 29B and from that reflector thence onto and througha translucent beam-spreading optical element 95 (which may be a convexFresnel or other lens, a lenticular diffusing sheet, a translucentopal-like diffuser, etc.) thereby spreading the transmitted light intothe illuminated space below. The optical assembly designs may receivethe light rays 8D emanating from a light pipe and pass them through atranslucent beam-spreading optical element 95, thereby spreading thetransmitted light and sending it onto portions of the nearby ceilingand/or a vertical surface, which may illuminate the ceiling and/or thevertical surface or area or some object toward which such light rays aredirected, as illustrated in FIG. 29C.

FIG. 30 illustrates the use of an optical element 17 (such as a Fresnellens, a negative lens, or any type of diffusing optical element) tospread light incident upon it as it passes through element 17 placed inan opening in the center of an optical distributor, in this case, forexample only, that distributor containing a crossfire section 11. FIG.30 also illustrates the use of an optical diffusing sheet 26, whichdiffusely transmits light rays incident upon it, with the emerging lightrays 8C spread angularly over the illuminated space below. If thediffusing sheet 20 is made larger than the distributor 10, it may servealso to receive stray light from the incident beam that fails to reachthe distributor 10 (or 100) and transmit that light diffusely to thespace below, thereby serving also as the stray rays blocking orredirecting ring 25 illustrated in FIG. 12.

The optical element 17 may spread the light rays 8A in the downwellingincident beam laterally over the optical diffusing sheet 26. The opticaldiffusing sheet 26 may be flat or curved, may be translucent, and may beplaced across the bottom 20 of distributor 10 in some embodiments. Theoptical diffusing sheet 26 may accept light rays 8B from the lens 17 andthen retransmit the light rays 8B as light rays 8C to diffuselyilluminate the area immediately below the optical distributor.

In some embodiments, the optical element 17 may be a flexible bundle ofglass or plastic fiber optics. The fibers in the bundle may be fully orpartially separated into individual or groups of fibers and each ofthese individual or groups may be routed inside the optical distributordown onto the optical diffusing sheet 26. The individual fibers orgroups of fibers may in some embodiments be arranged in customizedgeometric patterns to symbolize logos or textual information, whilestill providing additional illumination to the space immediately belowthe optical distributor, or the fibers may be arranged uniformly abovediffusely transmitting sheet 26 so as to illuminate it more uniformly.

FIG. 31 illustrates the use of optical distributors to illuminate one ormore walls 54 and 56 surrounding a space to be illuminated in additionto the ceiling (i.e. the first plane 30). The optical distributor 10shown in FIG. 31 may be slightly changed in shape so that the light raysin the cylindrically collimated beam are redirected by the opticaldistributor at least partially onto a receiving area 54 or 56 (such asone or more walls). The receiving area 54 or 56 may in some embodimentsbe parallel to the optical axis 5 but may be much larger in diameterthan the incident beam 8A surrounding the optical axis 5. The receivingareas may be, for example, the cylindrical wall 54 of a cylindricallyshaped foyer or stairwell entrance to a building, with an overheadceiling, or other geometries intended for other purposes, such as arectangular-walled 56 room. In this manner, the optical distributor mayilluminate both the ceiling and wall or walls of the space surroundingthe optical distributor. The light reflected diffusely from thesesurfaces may further illuminate the second plane 40 (such as the taskplane or the floor) of the space.

FIG. 32 illustrates the use of curved reflectors 34 placed alongportions of one or more walls and/or ceiling edge areas of a room toreflect rays 8C downward and radially outward as rays 8C onto the wallareas below them. The optical distributors 10 illustrated in FIG. 32 mayilluminate the first plane 30 within a room, and may also reflect somelight rays onto one or more specular reflectors 34, which may be placedin the space where a wall and ceiling are joined. The opticaldistributor 10 may in some embodiments be placed near the wall of thespace that is to be illuminated indirectly by reflector 34. Thereflector 34 may be curved such that it is designed to reflect rays 8Bfrom the optical distributor 10 down and radially outward from theoptical distributor and onto the wall below the reflector 34, asillustrated schematically in FIG. 32. The Incident beam of rays 8A mayreflect from the optical distributor 10 upward onto the first plane 30of the space. A portion of the reflected rays 8B may also propagate tothe one or more reflectors 34 which reflect the rays downward and ontothe wall below the reflector 34. This may illuminate the wall and thespace adjacent to the wall without producing glare.

FIG. 33 illustrates the use of an optical element 21 (such as a positiveFresnel or other lens) which may accept light rays 8B from thedownwelling beam of light rays 8A passing through aperture 34 in theoptical distributor 10 and concentrate those light rays of flux onto ahorizontal target surface area 41 below the optical element 21. Theoptical element 21 may in some embodiments manipulate and/or direct thedownwelling beam of light rays 8A to better meet the needs of transportand additional concentration of the light rays. In some embodiments, theoptical element 21 may be used in addition to or in place of an opticaldistributor.

In FIG. 33, an optical element 21 such as a Fresnel lens, may be placedin the downwelling beam 8A passing through aperture 32 in plane 30,which further passes through an aperture 34 in the optical distributor10 and then onto the optical element 21, which concentrates and focusesthe transmitted flux onto a target plane 41. The optical element 21 maybe used in order to irradiate a sample of material with concentratedsolar radiation for chemical purposes or to provide heat for amanufacturing process. By placing the target 41 at various distancesbelow lens 21, various degrees of concentration may be achieved.

FIG. 34 is similar to FIG. 33 except that an optical element 22 (such asa negative or diverging Fresnel or other lens) is added in order to, forexample, re-collimate the light rays. In some embodiments, the opticalelements 21 and 22 may be placed using confocal positioning, such thatthe quasicollimated, nearly parallel rays in the original beam of lightrays 8B, 8C are focused by the optical element 21 into a converging beamof light rays 8D which is intercepted by lens 22. The rays emerging fromthe optical element 22, for some distances between the optical elements21 and 22, may be approximately parallel, recollimating the originalbeam. Such an arrangement may be used in several implementations, suchas, for example, providing a smaller, more concentrated beam that can besent into a light pipe 80 for transport over some distance, asillustrated in FIG. 35 and described below. The embodiment shown in FIG.335 may be useful if there is limited space for the light beams to passthrough, in which case, the smaller beam diameter may allow for easierrouting of the light pipe, or for a flexible means of providing tasklighting.

FIG. 35 is similar to FIG. 34 except that a light pipe 80 is added inorder to, for example, transport the re-collimated light to a differentlocation. The light pipe 80 may be a cylindrical reflective light pipeas shown or it may be square, elliptical, or any other polygonal crosssection), and it may further be a total internal reflection light pipe,or any other suitable light pipe, including a prismatic-walled hollowlight guide.

It is here noted that for fairly well-collimated incident beams, acylindrical specularly reflective light pipe may exhibit a degree offocusing of the flux that varies in degree and location of focus alongthe length of the pipe. Altering the cross-sectional shape of the pipemay in some cases reduce or eliminate such focusing characteristics.Non-circular light pipes may also have advantages in loweringfabrication costs for some design applications.

FIG. 36 is similar to FIG. 35, except that an optical element 23 and anoptical element 24 are added. The optical element 23 may be a negativeor diverging lens, or other type of optical element, and the opticalelement 24 may be a positive or converging Fresnel lens, or other typeof optical element. 3 2 2 2 The light pipe 80 may transport a compact,concentrated beam of light rays, which, upon emerging from the lightpipe, may pass through optical element 23. The optical element 23 mayspread the beam of light rays, which beam may then pass through theoptical element 24 in order to, for example, re-collimate the beam witha larger diameter beam that is less concentrated and may be further usedelsewhere. The embodiment illustrated in FIG. 36 may be used, forexample, to transport a concentrated version of the original beamcompactly through a reduced-diameter light pipe 80 or a flexible fiberoptics bundle to a nearby location and then to spread the beam emergingfrom the light pipe to a less concentrated form, the less concentratedform being perhaps less likely to cause damage, and be useful for localtask lighting with high intensity. The embodiment shown in FIG. 36 mayalso help reduce material costs and make a more compact design.

Referring now to FIGS. 37, 38, 39, 40, and 41, the sizes, positions, andinclinations of the segmented portions or facets of various embodimentsof a narrow optical distributor 100, described previously in connectionwith FIG. 21 and following, may be determined by the process describedbelow. As mentioned above, other processes may be used in addition to orin place of the following. A narrow optical distributor 100 may be usedin some instances when the desired spreading of the downwelling beam isnot desired to fill a complete 360-degree horizontal circular zoneradiating outward from the beam, but instead is desired to propagateonly in two opposite directions, with perhaps a small amount of lateral(horizontal) spreading of the two opposing beams. This may be thedesirable, for example, to illuminate a narrow aisle. The narrow opticaldistributor 100 may be shaped like a “rooftop” in some embodiments andmay include two intersecting faceted planar reflectors joined at thecommon line where their top edges are joined and which are nominallyangled near to 45 degrees either side of the vertical.

FIG. 37 illustrates a schematic illustration of the way that thedownwelling flux in a rectangular beam of light rays 8A passing throughrectangular aperture 32 in first plane 30 may be intercepted by segmentsor facets of the narrow optical distributor 100 and the way that thisflux is reflected by the distributor 100 into multiple rectangular bandsof radiant flux in the first plane 30, centered on the optical axis 5.One possible faceting of the two sides of distributor 100 is shown inFIGS. 38 and 39, which show also a stray rays intercepting segment 125.The coordinate system chosen is a planar Cartesian one, with coordinatesr and y. The usual x coordinate, illustrated as x and simultaneously asr in FIG. 40, is measured outward from optical axis 5. When themeasurement is made in the first plane 30 the coordinate may bedesignated x. When it is made from the optical axis to the distributor100 it may be designated r. The vertical coordinate, illustrated as y inFIG. 40, is measured vertically downward from the first plane 30. Asshown in FIGS. 39, 40, and 41, each line segment 100A, 100B, etc., maybe used to generate a segment or facet of the optical distributor bysweeping that line segment in one direction, along the Z direction thatis perpendicular to the plane of the drawing of FIG. 40, by a distanceequal to the desired width of distributor in that Z direction, orsweeping line segments in a plane passing through the optical axis 5equally in opposite directions from that plane. The i^(th) line segmentmay be defined by an inner x-coordinate r, and an x-increment beingdenoted Δr_(i), with i ranging from 1 to N, where N is the number ofsegments in the optical distributor, and by a top y-coordinate, denotedy_(i) and a y-increment being denoted Δy_(i), respectively. (Unlike thecase of the other embodiments of optical distributors, facets ofdistributor 100 shown in FIGS. 37-41 may be contiguous and/or connectedto each other by common edges.) Note that FIGS. 40 and 41 illustrateonly one half of the linear distributor 100. The other half is aduplicate of the first half following rotation about the optical axis 5through an angle of 180 degrees.

FIG. 37 shows an isometric view of an embodiment of a linear opticaldistributor 100 that may distribute radiation initially propagating in acollimated beam of light rays 8A, which, following passage from thesource through rectangular, elliptical, circular, or polygonal aperture32 in a first plane 30, is incident on the linear optical distributorand thence reflected by that distributor as reflected rays 8B towards abottom surface of the first plane 30 (which may in some embodiments be anominally rectangular diffusing plane). The linear optical distributormay also be referred to as a narrow beam optical distributor, a narrowdistributing reflector, a reflective wedge, a rooftop-shaped reflector,a reflector, a distributor, and so forth, but here may be referred tosimply as a linear optical distributor to distinguish it from the radialoptical distributor described previously. The linear optical distributor100 may in some embodiments be faceted, reflective, rectangular,elliptical, etc., and the incident beam of light rays 8A propagated tothe linear optical distributor may be reflected toward two opposingdirections as rays 8B. The linear optical distributor 100 may becomprised of two duplicate, mirror imaged, intersecting faceted planarreflectors. The rectangular facets illustrated in FIG. 37 may reflectlight from beam 8A upward and onto the bottom side of first plane 30,where that light may be reflected onto a second, parallel plane 40perpendicular to the optical axis 5 of the system. In an alternateembodiment of distributor 100, the nominally rectangular planar facetsof distributor 100 may be bent along their lengths so as to spread thebeams reflected from each one laterally, spreading the reflected beamleft and right as it propagates toward the left and right in FIG. 37,down a narrow hallway or aisle, for example. The tilts of the facets ofdistributor 100 about the horizontal common edges between them may insome embodiments distribute a modest amount of radiant flux to thebottom of plane 30 in the region close to the aperture 32 and increasingquantities of this flux at increasing distances left and right fromaperture 32. The collimated beam of rays 8A may come from an electriclight source system or from a solar collecting and concentrating system.In both cases, the rays 8A in the beam may be well-collimated (varyinglittle from being parallel to optical axis 5) or they may be“quasi-collimated” (meaning that they vary from a small angle, e.g., 0.5degree up to approximately 5 or 10 degrees from the direction of theoptical axis 5). The embodiments described herein may function less wellif the incident beam 8A is less collimated, or they may not, dependingupon the intended application of this invention. However, theembodiments presented herein are intended for use with collimated andquasi-collimated incident beams.

The radiant flux reflected from the first plane 30 shown in FIG. 37 maysubsequently be approximately uniformly distributed (e.g., withapproximately constant irradiance or illuminance) across a second plane40, with the second plane 40 being not far below the first plane 30 insome embodiments, or the illumination distribution following reflectionfrom plane 30 may be substantially varying, with higher flux sent byeach facet or segment at increasing distances from aperture 32 tocompensate for increasing light spreading with distance. In otherembodiments, the second plane 40 may be far below the first plane 30.The second plane 40 may be parallel, and may be, for example, the flooror task plane of a space to be illuminated, but it may alternatively beany target plane or area to be illuminated or irradiated. The nominallyelongated first and second planes 30 and 40 for the linear distributor100 may be much longer than they are wide, as with aisles betweenstorage racks or a hallway in a building, but the applications are notconfined to these. For example, the linear distributor 100 may be usedfor large area lighting in an open plan office, warehouse, or otherlarge open space in a building, through the use of multiple beams 8A anddistributors 100 beneath them, each arranged, side by side, toilluminate the space in one direction by means of the distributors 100and in the other perpendicular direction by means of the multipleside-by-side beams and distributors.

The optical distributor 100 in FIG. 37 may thus redirect or distributelight from the collimated beam into other directions in a controlledmanner. By increasing the number of vertically spreading beams ofreflected flux, and when used with a source such as a solar disk thatmay have a small natural angular spread, the individual beams of lighton the first plane 30 may be broadened by the slight vertical angularspreading and fill the target area of the first plane 30 more uniformly.As such, the linear optical distributor 100 may illuminate some, most,or all of the second plane 40 in an approximately uniform manner. Also,the illumination of the first plane 30 is desired in most but not allpossible embodiments not to be overly discontinuous or too bright at anyparticular location as a result of the optical distributor 100redirecting the light rays. By making the number N of facets or segmentsof linear optical distributor 100 larger than, for example, 10 or more,the discontinuous appearance of the reflected flux reaching plane 30 canbe ameliorated somewhat. Other means of producing a more uniform, lessdiscontinuous illumination of plane 30 are described subsequently.

It may be desirable in some but not all embodiments to prevent thesmaller area of plane 30 immediately above and hence closer todistributor 100 from being excessively brighter than areas of plane 30further outward, which may then be too dim, by varying the quantity offlux distributed to plane 30 so that most of the flux fills the greaterareas at the outer ends of plane 30.

In some embodiments, the optical distributor 100 may include one or moresegments of one or more rectangular reflective facets (rectangles orsections), some or all of which may have a slightly different angle froma vertical line through the center of the optical distributor, which maybe the axis 5 of optical distributor 100. The facets or faceted surfaces(or the segments thereof) of the optical distributor 100 may furtherhave slightly altered widths and tilts so that the illuminance orirradiance along the two beams of light reaching the first plane 30 fromdistributor 100 may be, on average, approximately uniform, therebydistributing the light across the second plane 40 somewhat evenly.

In this and other embodiments, the optical distributor 100 may includesmooth and continually sloping, rectangular optical distributor surfacesthat also may re-direct or distribute a portion of a downwellingcollimated beam of light rays 8A back upward and outward onto a firstplane 30 in such a manner that the light from the optical distributorthat is subsequently reflected diffusely from the first plane 30 maythereafter be generally uniformly distributed over a second plane 40below the optical distributor 100.

Many variations of the radial optical distributor 100 shown in FIG. 37are possible. For example, the first plane 30 may have a lower surfacethat is diffusely reflecting, and the surface may have any perimeter,shape, width, etc. The first plane 30 may have an elliptical orpolygonal opening 32 in its center, may be centered around the opticalaxis 5 of the optical distributor 100 (as illustrated in FIG. 37).Furthermore, the top or peak of the linear optical distributor 100 maybe located at any distance below the first plane 30. As described belowin more detail, some embodiments of the linear optical distributor 100may be low-profile in order to reduce the distance that the opticaldistributor 100 extends below the first plane 30. In other embodiments,a stack of shallow rectangular glare shields may be placed on eitherside (left and right in FIG. 37) and above at least a portion of theoptical distributor. Still other embodiments, as described below,include one or more tilted reflective mirrors that may be circularly orrectangularly shaped and which may reflect a portion of the verticaldownwelling collimated beam of light rays laterally and upwardly outwardfrom the central axis of the beam, while spreading the light rayslaterally and optionally in the two perpendicular direction as well, toilluminate one or more limited portions of the surrounding space withcontrolled levels of illumination.

Although the nominal shape of the incident beam of light rays 8A shownin FIG. 37 is approximately rectangular and may result in approximatelyuniform irradiance or illuminance in the reflected light when used witha linear optical distributor 100, other shapes of incident light beamsand/or other shapes of optical distributors are possible. Incident lightrays may form beams with circular, polygonal, or ellipticalcross-sections, or any other type of beam, including a beam with anirregular cross section. The optical distributor 100 may beappropriately modified for differing incident beam shapes. For example,in the case of an elliptical light beam, the optical distributor mayhave a perimeter, when projected onto plane 30 that is elliptical, tomatch the envelope of the incident beam.

The optical distributor 100 may in some cases be used to illuminate aroom or a portion thereof using solar light collected by a lightgathering system. In some embodiments, the system may be located on arooftop, and may deliver a generally fixed, nominally cylindrical beamof light downward through the roof and ceiling and onto the opticaldistributor using a single roof penetration.

FIG. 38 shows an isometric view of the linear optical distributor 100,and the rectangular reflective facets 100A, 100B, 100C, 100D, and 100Eof a five-faceted version and a stray light blocking or reflectingadditional reflector 125 that is just outside the nominal envelope ofthe incident beam of rays 8A. FIG. 39 shows side plan view of an opticaldistributor 100 with five faceted surfaces (100A, 100B, 100C, 100D, and100E) and a stray rays blocking edge 125. The blocking edge 125 may, insome embodiments, be opaque, absorbing, reflecting, and/or diffusing,and may be located adjacent to the left and right bases of the opticaldistributor 100 and extend some distance laterally (left and right inFIG. 39) outward beyond the left and right base edges of the opticaldistributor 100. The blocking edge 125 may redirect flux from theincident beam of light rays 8A and cause that flux to propagatelaterally outward beyond the perimeter of the base of the opticaldistributor 100 and thence upward onto first plane 30, which flux mightotherwise cause a glare or stray light condition if allowed to continuedown into the occupied space. Many variations on the blocking component125 shown in FIGS. 38 and 39 are possible. In some embodiments anoptical diffusing sheet may be used in conjunction with or in place ofthe blocking edge 125 to capture and/or absorb or diffuse stray lightfrom the source that misses the segmented distributor 100.

FIGS. 40-41 show a schematic diagrams of portions of an opticaldistributor 100, the first plane 30, and aperture 32 in plane 30, withvarious geometrical lines, dimensions, and angles illustrated for use inexplaining various mathematical steps that may be used in someembodiments to compute potential dimensions of some embodiments of theoptical distributor 100. Both FIGS. 40 and 41 illustrate only portionsof the left half of linear optical distributing reflector 100. Referringto FIG. 40, the line 5 may be an axis through the center of the opticaldistributor 100, denoted as the y-axis, and line 30 in FIG. 40 coincideswith and corresponds to the first plane 30 in FIG. 37, and is denotedthe X-axis in FIG. 40. The left half of the full distributor 100 isdepicted in FIG. 40 as a slightly curved line. For the purposes of thisgeometrical discussion, it may be composed of several straight linesegments. The X distance from line 5 to the inner edge of thedistributor 100 closest to line 5 is denoted r_(in) and the X distanceto the outer edge of distributor 100 farthest from line 5 is denotedr_(out).

Still with reference to FIG. 40, an optical distributor 100 may berealized by defining a set of coplanar line segments 10A, 10B, 10C, 10D,and so forth, in the x-y plane of the rectangular coordinate system usedin FIGS. 40 and 41, these line segments also depicted in FIG. 39, andthen sweeping these coplanar line segments in a linear manner along theZ direction perpendicular to the x-y plane of the drawing in FIG. 40,equal distances on either side (in and out) of that plane, to form atwo-dimensional rectangular segmented surface perpendicular to the x-yplane of the drawings in FIGS. 39 and 40. Such an operation willgenerate one half of the linear optical distributor. The other half isgenerated by duplicating the half just created, then rotating it aboutthe optical axis 5 through an angle of 180 degrees. The x widths, ylengths, and tilt angles of the facets or segments of the opticaldistributor 100 may be selected to reflect light into rectangular areasin the first plane 30 in such a manner that the light rays diffuselyreflected from the first plane 30 are approximately uniformlydistributed across the second plane 40.

In FIG. 40, a downwelling flux of light rays parallel to line 5 andstriking distributor 100 may strike the line segments, 100A, 100B, 100C,100D, and 100E in the five-segment or five-facet optical distributor 100shown in FIG. 38. The flux may reflect specularly up and horizontally tothe left of the left half of optical distributor shown in FIG. 40, withrays at the ends of the half-distributor 100 propagating onto the firstplane 30, shown as lines 8B_(in) and 8B_(out) on FIG. 40. The angles ofincidence of these rays on the inner and outer segments of thishalf-distributor are shown as α_(in) and α_(out) in FIG. 40. Measuringthe distance down from the first plane 30 as coordinate y and radialdistances to the left from the optical axis 5 as coordinate r, linesegment 100A has top right coordinates (r₁, y₁). Because in this designmethod, it is assumed that the bottom left of the first line segment100A is connected to and has the same coordinates as the top right ofthe second line segment 100B, the bottom left coordinates of the firstline segment are here designated (r₂, y₂). 1 1 1

As with the radial optical distributor 10 described previously, there isno inherent restriction that the segments to be connected in thismanner. As before, for aesthetic or other reasons, the verticalseparation between each facet or segment of optical distributor 10 canbe greater than zero, but this method for calculating the coordinates ofthe end points of each generating line needs to be modified accordingly.An exemplary embodiment of the optical distributor 10 with verticallyseparated facets of segments is shown in FIG. 2B. Rays reflecting fromthe distributor 100 may propagate until they strike the first plane 30between coordinates x_(in) and x_(out), respectively. Referring to FIG.40, the corresponding distances down from plane 30 to where these raysmay strike the inner and outer edges of distributor 100 are designatedy_(in) and y_(out), respectively. The angle between the rays reflectedfrom the inner and outer edges of the distributor and the vertical are2α_(in) and 2α_(out), respectively, since the angles of incidence α_(in)and α_(out) relative to the dashed line perpendiculars to thedistributor reflecting surface at its inner and outer limits,respectively, equal the same-sized angles of reflection.

Certain mathematical operations will now be described with reference toFIGS. 40 and 41. These mathematical operations may be used in designingsome but not all embodiments of a linear optical distributor. Othermathematical operations may be used in place of, or in addition to thoseexplained below. Also, the mathematical operations explained below maybe modified in some instances.

FIG. 41 illustrates the geometrical relationships involved when incidentrays 8A are incident on the inner and outer edges of the i^(th) planarreflector facet, counting from 1 at x-coordinate r₁=r_(in) to the N^(th)facet inner edge at r_(N)=r_(out) in a linear optical distributor. Asjust mentioned, in the currently considered embodiment, the facets ofdistributor 100 are all connected at their adjacent edges. The dashedlines in FIG. 41 are normal or perpendicular to the i^(th) facetsurface. The angles of incidence and reflection may be equal anddesignated as α_(i). The angle θ_(i) between a vertical line in FIG. 41and rays reflected from the ith facet may equal twice the angle ofincidence α_(i).θ_(i)=2α_(i)  (119)The complement of θ_(i) is designated cθ_(i) and may be equal to90°−θ_(i).cθ _(i)=90°−θ_(i)  (120)

Rays incident in the inner and outer edges of the i^(th) facet atx-coordinates r, and r_(i+1), respectively, and at correspondingy-coordinates, y_(i) and y_(i+1), respectively, intersect the firstplane 30 at x-coordinates, x_(i) and x_(i+1), respectively. To solve thegeometry shown in FIG. 41, a line of length w_(i) may be constructedfrom the intersection point of the ray reflected from the inner edge ofthe i^(th) facet to the point on the ray reflected from the outer edgethat makes the two lines perpendicular. The two angles inside thetriangle formed by the reflected ray, the perpendicular line and theline segment of width Δx_(i) on plane 30 are designated cθ_(i) and θ_(i)on FIG. 41. Next, another such line may be constructed from the outeredge of the i^(th) facet to the ray reflected from the inner edge ofthat facet. Since the two rays are parallel, these two lines have thesame length, w_(i), as illustrated in FIG. 41. The width of the i^(th)facet may be denoted w_(i)′.

The inputs to the calculation sequence may be the known designparameters for the distributor shown in FIG. 40: y_(in), r_(in),r_(out), x_(in), and x_(out). The missing design parameters which haveto be calculated are: y_(out), h_(out), and all the r_(i) and y_(i). Aniterative sequence may be used in some embodiments to determine themissing coordinates of the edges of each of the N facets of thedistributor. The inner edge of the distributor may be at x=r_(in)=r₁ andy=y_(in)=y₁. The outer (and lower) edge may be at r_(out), which thedesigner should set to be approximately equal to or slightly greaterthan the half-width of the incident downwelling beam for the distributorto be large enough to intercept all the rays in the incident beam.

Since the x width of the distributor may be fixed by the size of theincident beam, a design parameter, the values of the end points of the xrange may be known, i.e. r_(in) and r_(out). If the distributor is tohave N facets, the x widths of all of them may be equal and may be givenby Δr using equation 121:Δr=(r _(N) −r ₁)/N  (121)where r_(N) is equal to the half width or radius of the distributor.Thus the value of the i^(th) x-coordinate for the inner edge of thei^(th) facet may be given by r, in equation 122:r _(i) =r ₁+(i−1)Δr  (122)From the geometry of FIG. 41, it follows thattan α_(i) =Δy _(i) /Δr  (123)cos α_(i) =Δr/w _(i)′  (124)Δy _(i) =w _(i)′ sin α_(i)  (125)cos θ_(i) =w _(i) /Δx  (126)sin α_(i) =Δy _(i) /w _(i)′  (127)α_(i)=θ_(i)/2  (128)The calculation sequence is therefore as follows:From the design inputs, we know that r₁=r_(in), x₁=x_(in)=arctan(x₁/y₁),α₁=θ_(i)/2, w₁=Δx cos θ₁, w₁′=Δr/cos α₁ and r_(i)=r₁+(i−1)Δr for any i.

For values of i from 1 to N, the remaining values of r_(i) and y_(i) maybe calculated as follows:r _(i) =iΔr; θ _(i)=arctan(x _(i) /y _(i)); w _(i) =Δx cos θ_(i)  (129)α_(i)=θ_(i)/2; w _(i) ′=Δr/cos α_(i) ; Δy _(i) =w _(i)′ sin α_(i)  (130)y _(i) =y _(i−1) +Δy _(i−1) r _(i) =r ₁+(i−1)Δr  (131)until the end when i=N. This gives the coordinates r_(i) and y_(i) forthe starting ends of each of the line segments used to generatedistributor 100 by this method. The coordinates for the starting end ofthe i+1 line equal those of the ending end of the i line.Once the set of generating facets for half the distributor has beencalculated, half the distributor may be extruded by sweeping these linesin directions in and out of the plane of their existence. The set ofreflecting facets generated for the first half-distributor may bemirrored and used on the other side of the optical axis 5 for the otherhalf-distributor, thereby completing the design of the lineardistributor. The above embodiment may be based on a constant value of Δrfor all facets, meaning that each one may intercept the same portion ofa substantially uniform rectangular downwelling beam. If the downwellingbeam is elliptical in nature, then the equal Δr x-widths of each facetmay intercept a decreasing quantity of flux, declining to near zero forthe last facet at the outer limit of the beam. To produce more uniformillumination of plane 30, one may replace (121) with a substituteformula that increases Δr by some exponent as the value of i increasesfrom 1 to N, while still leaving the sum equal to r_(max) at i=N. If Δris increased with increasing values of i, this may put more lightfurther away from the optical axis than otherwise, and vice versa.

To achieve this while still having the individual Δr_(i) sum tor_(N)−r₁, as described in Eq. 132,ΣΔr _(i) =r _(N) −r ₁  (132)one design choice may be to increase Δr_(i) linearly with i as in (133),using the proportionality constant k.Δr _(i) =ik  (133)Substituting (133) for Δr_(i) into (132) and solving for k yieldsk=(r _(N) −r ₁)/Σi  (134)To evaluate this equation, the Sum Of Integers function (70) may beused, resulting in the following:k=2(r _(N) −r ₁)/(N(N+1))  (135)Using this in Eq. (133) results in the following formula for the Δr_(i)that meets the constraints of this approach:Δr _(i)=2i(r _(N) −r ₁)/(N(N+1))  (136)Since the sum of the Δr_(j−1) from j=1 to i must equal r_(i), we canexpress the r_(i) values as follows:

$\begin{matrix}{r_{i} = {{\sum\limits_{j = 1}^{i}\;{\Delta\; r_{i - 1}}} = {{\sum\limits_{j = 1}^{i}\;{\left( {i - 1} \right)k}} = {\sum\limits_{j = 1}^{i}\;{\left( {i - 1} \right)\frac{2\;{i\left( {r_{n} - r_{1}} \right)}}{N\left( {N + 1} \right)}}}}}} & (137)\end{matrix}$

The above formula may result in a linear increase in Δr_(i) with i,according to the constant k of proportionality as indicated in (133).Alternatively, the exponent of i in that equation may be changed fromthe implied value of 1.0 to a value slightly higher or slightly lower,as illustrated in Eq. 138,r _(i) =i ^(n) Δr  (138)where n is any real value somewhat larger or smaller than 1.0. Such achange may increase or decrease the rate at which Δr_(i) changes withincreasing i. This approach may provide control over the distribution ofreflected radiation from the optical distributor onto the first plane 30and to some extent also onto plane 40. The use of an exponentialvariation of Δr_(i) with i as indicated in Eq. 138, is only one choice.Many other choices may be made to suit the particular application forwhich the invention is intended.

The embodiment of a linear distributor described above may besusceptible, when used for illumination of spaces in buildings with lowceilings, to a glare condition. The glare may be produced by excessivequantities of light flux reflecting from distributor 100 in a diffuselyscattered manner directly down into the space below the height of thatdistributor due to dust, dirt, surface roughness or other opticalimperfections, rather than being specularly reflected upward and outwardonto the first plane 30. This condition may in some embodiments bealleviated through the use of glare shields 170 such as thoseillustrated in FIG. 42. These shields may be made of thin planar sheets170 of opaque material positioned just beyond either longitudinal end ofdistributor 100, so as not to impede rays 8A in the downwellingquasi-collimated beam from reaching the distributor 100. Said sheets maythen be angled in such a way as to be approximately parallel to thereflected rays 8A emanating from the distributor 100 toward the firstplane 30 while blocking a view of the distributor 100 from any locationin the space below the bottom of the distributor. Since some light mayscatter laterally away from the distributor 100 shown in FIG. 42 (in andout of the plane of the drawing), around the ends of the glare shields170, two additional vertical opaque or diffusely transmitting sheets(not shown on FIG. 42) may be placed on either side of distributor 100,the front and back sides of distributor 100 illustrated in FIG. 42.These additional vertical glare shields may be particularly useful forillumination of a large area. Other embodiments of these additionalglare shields are possible, such as angled louvered sheets to replacethe vertical monolithic ones, or a continuation of the two stacks ofglare shields depicted in FIG. 42 around the whole distributor 100.

For low-bay applications of the linear distributor design, it may bedesirable to reduce the overall height of the distributor 100, to reducethe penetration of the distributor downward from the ceiling plane 30into the occupied space below. Accordingly, the optical distributor 100design depicted in FIG. 38 may be truncated in some embodiments,removing, for example, sections 100A and 100B and then filling the holethereby created with new versions of 100A and 100B, and their mirroredcounterparts on the other half of distributor 100, the newly sized andpositioned 100A and 100B descending downward into the hole, asillustrated in FIG. 43. This altered design may create a crater or a“crossfire” section of the distributor. The crossfire section ofdistributor 100 depicted in FIG. 43 may reclaiming the downwelling rays8A in the incident beam that might otherwise be lost through the hole indistributor 100 (created by removing sections 100A and 100B from it) andreflecting said rays upward and laterally outward, over the top edge ofthe opposite half of the new distributor 100. The angular orientation ofthe new descending sections of the distributor may reflect rays incidentupon them over the ridge opposite them and thence upward and outwardonto first plane 30. As in previous embodiments, this “crossfire”low-profile embodiment can be given a small slot in the center bysetting r_(in) to something greater than zero. As with the radialdistributor 10 described previously, the incident radiation passingthrough this center slot or hole in distributor 100 may be spread by oneor more lenses and diffusing sheets to control the spread of thatradiation below the distributor.

As described in detail above in connection with the optical distributor10, various steps may be taken in some embodiments to overcome thebinary illumination of the first plane 30 by the optical distributor100. These include the use of a large number N of facets in theconstruction of the distributor and, in another embodiment, fitting amathematical curve to the end points having coordinates (r_(i), y_(i))and using the fitted curve to generate a smooth linear opticaldistributor 100 without facets.

An exemplary computer system 400 for implementing the processesdescribed above for generating the size, angle, and form of an opticaldistributor is depicted in FIG. 44. The computer system 400 of adesigner may be a personal computer (PC), a workstation, a notebook orportable computer, a tablet PC, a handheld media player (e.g., an MP3player), a smart phone device, a video gaming device, or a set top box,with internal processing and memory components as well as interfacecomponents for connection with external input, output, storage, network,and other types of peripheral devices. Internal components of thecomputer system in FIG. 44 are shown within the dashed line and externalcomponents are shown outside of the dashed line. Components that may beinternal or external are shown straddling the dashed line. Alternativelyto a PC, the computer system 400, for example, for running the opticaldistributor form generation application, may be in the form of any of aserver, a mainframe computer, a distributed computer, an Internetappliance, or other computer devices, or combinations thereof.

In any embodiment or component of the system described herein, thecomputer system 400 includes a processor 402 and a system memory 406connected by a system bus 404 that also operatively couples varioussystem components. There may be one or more processors 402, e.g., asingle central processing unit (CPU), or a plurality of processingunits, commonly referred to as a parallel processing environment (forexample, a dual-core, quad-core, or other multi-core processing device).The system bus 404 may be any of several types of bus structuresincluding a memory bus or memory controller, a peripheral bus, aswitched-fabric, point-to-point connection, and a local bus using any ofa variety of bus architectures. The system memory 406 includes read onlymemory (ROM) 408 and random access memory (RAM) 410. A basicinput/output system (BIOS) 412, containing the basic routines that helpto transfer information between elements within the computer system 400,such as during start-up, is stored in ROM 408. A cache 414 may be setaside in RAM 410 to provide a high speed memory store for frequentlyaccessed data.

A hard disk drive interface 416 may be connected with the system bus 404to provide read and write access to a data storage device, e.g., a harddisk drive 418, for nonvolatile storage of applications, files, anddata. A number of program modules and other data may be stored on thehard disk 418, including an operating system 420, one or moreapplication programs 422, and data files 424. In an exemplaryimplementation, the hard disk drive 418 may store the opticaldistributor form generation application 466, the input data repository426 for storage of various input dimensions described above for use bythe optical distributor form generation application to design an opticaldistributor, and an output data repository 466 for storing designs ofoptical distributors created according to the exemplary processesdescribed herein above. Note that the hard disk drive 418 may be eitheran internal component or an external component of the computer system400 as indicated by the hard disk drive 418 straddling the dashed linein FIG. 44. In some configurations, there may be both an internal and anexternal hard disk drive 418.

The computer system 400 may further include a magnetic disk drive 430for reading from or writing to a removable magnetic disk 432, tape, orother magnetic media. The magnetic disk drive 430 may be connected withthe system bus 404 via a magnetic drive interface 428 to provide readand write access to the magnetic disk drive 430 initiated by othercomponents or applications within the computer system 400. The magneticdisk drive 430 and the associated computer-readable media may be used toprovide nonvolatile storage of computer-readable instructions, datastructures, program modules, and other data for the computer system 400.

The computer system 400 may additionally include an optical disk drive436 for reading from or writing to a removable optical disk 438 such asa CD ROM or other optical media. The optical disk drive 436 may beconnected with the system bus 404 via an optical drive interface 434 toprovide read and write access to the optical disk drive 436 initiated byother components or applications within the computer system 400. Theoptical disk drive 430 and the associated computer-readable opticalmedia may be used to provide nonvolatile storage of computer-readableinstructions, data structures, program modules, and other data for thecomputer system 400.

A display device 442, e.g., a monitor, a television, or a projector, orother type of presentation device may also be connected to the systembus 404 via an interface, such as a video adapter 440 or video card.Similarly, audio devices, for example, external speakers or a microphone(not shown), may be connected to the system bus 404 through an audiocard or other audio interface (not shown).

In addition to the monitor 442, the computer system 400 may includeother peripheral input and output devices, which are often connected tothe processor 402 and memory 406 through the serial port interface 444that is coupled to the system bus 406. Input and output devices may alsoor alternately be connected with the system bus 404 by other interfaces,for example, a universal serial bus (USB), an IEEE 1394 interface(“Firewire”), a parallel port, or a game port. A user may enter commandsand information into the computer system 400 through various inputdevices including, for example, a keyboard 446 and pointing device 448,for example, a mouse. Other input devices (not shown) may include, forexample, a joystick, a game pad, a tablet, a touch screen device, asatellite dish, a scanner, a facsimile machine, a microphone, a digitalcamera, and a digital video camera.

Output devices may include a printer 450 and one or more loudspeakers470 for presenting the audio performance of the sender. Other outputdevices (not shown) may include, for example, a plotter, a photocopier,a photo printer, a facsimile machine, and a press. In someimplementations, several of these input and output devices may becombined into single devices, for example, aprinter/scanner/fax/photocopier. It should also be appreciated thatother types of computer-readable media and associated drives for storingdata, for example, magnetic cassettes or flash memory drives, may beaccessed by the computer system 400 via the serial port interface 444(e.g., USB) or similar port interface.

The computer system 400 may operate in a networked environment usinglogical connections through a network interface 452 coupled with thesystem bus 404 to communicate with one or more remote devices. Thelogical connections depicted in FIG. 44 include a local-area network(LAN) 454 and a wide-area network (WAN) 460. Such networkingenvironments are commonplace in home networks, office networks,enterprise-wide computer networks, and intranets. These logicalconnections may be achieved by a communication device coupled to orintegral with the computer system 400. As depicted in FIG. 44, the LAN454 may use a router 456 or hub, either wired or wireless, internal orexternal, to connect with remote devices, e.g., a remote computer 458,similarly connected on the LAN 454. The remote computer 458 may beanother personal computer, a server, a client, a peer device, or othercommon network node, and typically includes many or all of the elementsdescribed above relative to the computer system 400.

To connect with a WAN 460, the computer system 400 typically includes amodem 462 for establishing communications over the WAN 460. Typicallythe WAN 460 may be the Internet. However, in some instances the WAN 460may be a large private network spread among multiple locations, or avirtual private network (VPN). The modem 462 may be a telephone modem, ahigh speed modem (e.g., a digital subscriber line (DSL) modem), a cablemodem, or similar type of communications device. The modem 462, whichmay be internal or external, is connected to the system bus 418 via thenetwork interface 452. In alternate embodiments the modem 462 may beconnected via the serial port interface 444. It should be appreciatedthat the network connections shown are exemplary and other means of andcommunications devices for establishing a network communications linkbetween the computer system and other devices or networks may be used.

The technology described herein may be implemented as logical operationsand/or modules in one or more systems. The logical operations may beimplemented as a sequence of processor-implemented steps executing inone or more computer systems and as interconnected machine or circuitmodules within one or more computer systems. Likewise, the descriptionsof various component modules may be provided in terms of operationsexecuted or effected by the modules. The resulting implementation is amatter of choice, dependent on the performance requirements of theunderlying system implementing the described technology. Accordingly,the logical operations making up the embodiments of the technologydescribed herein are referred to variously as operations, steps,objects, or modules. Furthermore, it should be understood that logicaloperations may be performed in any order, unless explicitly claimedotherwise or a specific order is inherently necessitated by the claimlanguage.

In some implementations, articles of manufacture are provided ascomputer program products that cause the instantiation of operations ona computer system to implement the invention. One implementation of acomputer program product provides a computer program storage mediumreadable by a computer system and encoding a computer program. Anotherimplementation of a computer program product may be provided in acomputer data signal embodied in a carrier wave by a computing systemand encoding the computer program. It should further be understood thatthe described technology may be employed in special purpose devicesindependent of a personal computer.

A variety of embodiments and variations of structures and methods aredisclosed herein. Where appropriate, common reference numbers and wordswere used for common structure and method features. However, uniquereference numbers and words were sometimes used for similar or the samestructure or method elements for descriptive purposes. As such, the useof common or different reference numbers or words for similar or thesame structural or method elements is not intended to imply a similarityor difference beyond that described herein.

All directional and relative references (e.g., upper, lower, left,center, right, side, lateral, front, middle, back, rear, top, bottom,above, below, vertical, horizontal, and so forth) are given by way ofexample to aid the reader's understanding of the particular embodimentsdescribed. They should not be read to be requirements or limitations,particularly as to the position, orientation, or use of the inventionunless specifically set forth in the claims. Connection references(e.g., attached, coupled, connected, and joined, etc.) are to beconstrued broadly and may include intermediate members between aconnection of elements and relative movement between elements unlessotherwise indicated. As such, connection references do not necessarilyinfer that two elements are directly connected and in fixed relation toeach other, unless specifically set forth in the claims. The exemplarydrawings are for purposes of illustration only and the dimensions,positions, order and relative sizes reflected in the drawings attachedhereto may vary.

The above specification, examples, and data provide a completedescription of the structure and use of exemplary embodiments of theinvention as claimed below. Although various embodiments have beendescribed above with a certain degree of particularity, or withreference to one or more individual embodiments, those skilled in theart could make numerous alterations to the disclosed embodiments withoutdeparting from the spirit or scope of the claims. Other embodiments aretherefore contemplated. It is intended that all matter contained in theabove description and shown in the accompanying drawings shall beinterpreted as illustrative only of particular embodiments and notlimiting. Changes in detail or structure may be made without departingfrom the basic elements of the invention as defined in the followingclaims.

What is claimed is:
 1. An optical distributor comprising a reflectorwith one or more sloping surfaces, the plurality of sloping surfacescomprising a substantially pyramidal or conical frustum-shaped surface,the reflector further comprising a crater-shaped concave reflectorportion formed within a top portion of the substantially frustum-shapedsurface, wherein the one or more sloping surfaces have varying angles ofinclination from a bottom edge to a top edge of the reflector; and thereflector and the crater-shaped concave reflector portion are configuredto receive light rays through an opening in a first plane and reflectlight rays radially outward and upward at varying angles of reflectionto a bottom surface of the first plane in a manner that illuminates boththe bottom surface of the first plane and an area below the first plane.2. The optical distributor of claim 1, wherein the reflector isconfigured to illuminate both the bottom surface of the first plane andan area below the first plane in a substantially uniform manner.
 3. Theoptical distributor of claim 2, wherein the area illuminated in asubstantially uniform manner is a room in which the optical distributoris installed.
 4. The optical distributor of claim 1, wherein the anglesof inclination of each of the plurality of sloping surfaces varycontinuously in a linear form along the plurality of sloping surfacesfrom the bottom edge to the top edge of the reflector.
 5. The opticaldistributor of claim 1, wherein the angles of inclination vary in aplurality of discrete steps along the surface from the bottom edge tothe top edge.
 6. The optical distributor of claim 1, wherein theplurality of sloping surfaces comprise a plurality of adjacent annularbands that form faceted surfaces with respect to each other extendingfrom the bottom edge to the top edge; and each annular band defines adifferent angle of inclination.
 7. The optical distributor of claim 6,wherein the adjacent annular bands are contiguous with each other. 8.The optical distributor of claim 6, wherein the adjacent annular bandsare spatially separated from each other.
 9. The optical distributor ofclaim 1, wherein the area illuminated in a substantially uniform manneris a second plane.
 10. The optical distributor of claim 1, wherein thearea illuminated below the first plane is a second plane and is a taskplane.
 11. The optical distributor of claim 1, wherein the substantiallyfrustum-shaped surface defines an edge surrounding a base that iscircular.
 12. The optical distributor of claim 1, wherein thesubstantially frustum-shaped surface defines an edge surrounding a basethat is rectangular.
 13. The optical distributor of claim 1, wherein thesubstantially frustum-shaped surface comprises a plurality ofsubstantially frustum-shaped faceted surfaces.
 14. The opticaldistributor of claim 13, wherein the substantially frustum-shapedfaceted surfaces are annular bands.
 15. The optical distributor of claim13, wherein the substantially frustum-shaped faceted surfaces aretrapezoidal or rectangular.
 16. The optical distributor of claim 13,wherein one of the substantially frustum-shaped faceted surfaces isconcave.
 17. The optical distributor of claim 13, wherein one of thesubstantially frustum-shaped faceted surfaces is convex.
 18. The opticaldistributor of claim 1, wherein the plurality of sloping surfacescomprise a substantially pyramidal frustum-shaped surface; and a firstset of two opposing sides of the substantially pyramidal frustum-shapedsurface have a single angle of inclination that is normal to the firstplane.
 19. The optical distributor of claim 18, wherein a second set oftwo opposing sides of the substantially pyramidal frustum-shaped surfacecomprise a plurality of adjacent polygons that form faceted surfaceswith respect to each other extending from the bottom edge to the topedge; and each polygon defines a different angle of inclination withrespect to the first plane.
 20. The optical distributor of claim 1,further comprising a substantially convex frustum-shaped insertreflector mounted within the concave crater portion and positioned toreceive and reflect a further subset of the light rays.
 21. The opticaldistributor of claim 1, further comprising a first light pipe configuredto receive a portion of the light rays reflected by the reflector andtransport the received light rays to a remote location.
 22. The opticaldistributor of claim 1, further comprising a blocking edge adjacent thebottom edge.
 23. The optical distributor of claim 1, further comprisinga substantially pyramidal or conical frustum-shaped glare shieldadjacent the reflector and configured to prevent stray light rays fromentering the area below the first plane.
 24. The optical distributor ofclaim 23, wherein the glare shield absorbs the stray light rays.
 25. Theoptical distributor of claim 23, wherein the glare shield reflects thestray light rays.
 26. The optical distributor of claim 23, wherein thesubstantially frustum-shaped glare shield diffusely reflects the straylight rays.
 27. The optical distributor of claim 1, wherein thesubstantially frustum-shaped reflector defines an aperture in a centerof the substantially frustum-shaped reflector whereby a portion of thelight rays pass through the aperture.
 28. The optical distributor ofclaim 27 further comprising an optical element positioned with respectto the substantially frustum-shaped reflector to receive and manipulatethe portion of the light rays that pass through the aperture.
 29. Theoptical distributor of claim 28, wherein the optical element comprises aFresnel lens.
 30. The optical distributor of claim 28, wherein theoptical element comprises a simple lens.
 31. The optical distributor ofclaim 1, wherein the crater-shaped concave reflector portion defines anaperture in a center of the crater-shaped concave reflector portionwhereby a portion of the light rays pass through the aperture.
 32. Theoptical distributor of claim 31 further comprising an optical elementpositioned with respect to the substantially frustum-shaped reflector toreceive and manipulate the portion of the light rays that pass throughthe aperture.
 33. The optical distributor of claim 1, further comprisinga substantially pyramidal or conical frustum-shaped glare shieldadjacent the reflector and configured to diffusely transmit lightentering the area below the first plane.
 34. An optical distributorcomprising a reflector having a plurality of sloping surfaces comprisinga substantially pyramidal or conical frustum-shaped surface, eachsloping surface having an inner radius and an outer radius defining aradial width therebetween, and a crater-shaped concave reflector portionformed within a top portion of the substantially frustum-shaped surface,wherein the radial widths of each of the sloping surfaces increase forconsecutive sloping surfaces from a top edge to a bottom edge of thereflector and the sloping surfaces have varying angles of inclinationfrom the bottom edge to the top edge of the reflector, each angle ofinclination measured from a first plane above the reflector and normalto a longitudinal axis of the reflector; and the reflector andcrater-shaped concave reflector portion are configured to receive lightrays through an opening in the first plane and reflect light raysradially outward and upward at varying angles of reflection to a bottomsurface of the first plane in a manner that illuminates both the bottomsurface of the first plane and an area below the first plane.